Chemistry & Urinalysis and body fluids ASCP MLT medialab exams

Cells seen in the microscopic examination of the urine of a 30-year-old female, which are smaller than RBC's but much the same shape, are probably: - Yeast cells - Small lymphocytes - Squamous epithelial cells - Trichomonas vaginalis

- Yeast cells Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Lymphocytes, squamous epithelial cells, and trichomonas vaginalis are all larger than red blood cells.

Which of the following clinical laboratory departments performs the most tests? - Urinalysis - Microbiology - Clinical Chemistry - Hematology

- Clinical Chemistry Clinical Chemistry is the laboratory department that performs most laboratory tests, which include quantitative analytical procedures on various body fluids. This department may have sub-sections such as, Special Chemistry, Toxicology, Therapeutic Drug Monitoring, and Molecular Diagnostics. Urinalysis (UA) is the laboratory department that performs physical, chemical, and microscopic evaluation of urine. Microbiology is the laboratory department that cultures and identifies the presence of microorganisms from body fluids and tissues. This department may have sub-sections such as Bacteriology, Virology, Parasitology, Mycology, and Mycobacteriology. Hematology is the laboratory department which performs tests that identify diseases associated with blood and blood-forming tissues.

What is the lower reference limit for semen volume according to the World Health Organization, WHO Laboratory Manual for the Examination and Processing of Human Semen, 5th edition? - 0.5 mL - 1.5 mL - 3.5 mL - 4.5 mL

- 1.5 mL The typical ejaculate contains usually between 2-5 mL of semen. According to WHO's reference limits, the lower reference limit for semen volume is 1.5 mL. Volumes above or below the reference intervals are associated with infertility.

A routine laboratory workup is ordered for an outpatient. The patient's lipid results are as follows: Total cholesterol = 295 mg/dL HDL = 30 mg/dL Triglycerides = 200 mg/dL What is the LDL cholesterol level for this patient? - 225 mg/dL - 65 mg/dL - 365 mg/dL - 255 mg/dL

- 225 mg/dL LDL cholesterol = Total cholesterol - (HDL + (Trig / 5)) In this case, the calculation for LDL would be: LDL cholesterol = 295 mg/dL - (30 mg/dL + (200 mg/dL / 5)) LDL cholesterol = 295 mg/dL - 70 mg/dL = 225 mg/dL

Approximately how many doses are required to obtain a steady-state oscillation allowing for peak and trough levels to be evaluated? - 1 to 2 - 3 to 4 - 5 to 7 - > 10

- 5 to 7 Approximately five to seven doses are required before a steady-state oscillation is achieved. After the first dose, absorption and distribution occur, followed only by elimination. Before the concentration of the drug drops significantly, the second dose is given and the peak of the second dose is additive to what remains of the first dose. The third through the seventh scheduled doses all have the same effect, increasing the serum concentration and the amount eliminated. By the end of the seventh dose, the amount of the drug administered is equal to the amount eliminated during the dosage period. At this point, a steady-state is established and peak and trough concentrations can be evaluated.

Using the formula for creatinine clearance, calculate the clearance based on the values given below: Urine creatinine: 100 mg/dL Plasma creatinine: 1.9 mg/dL Urine volume: 1375 mL/24hrs Surface Area: 1.2 m2 Round to 1 decimal place. - 1.04 x 105 mL/min/m2 - 1.04 x 105 mL/min - 72 mL/min/m2 - 72 mL/min

- 72 mL/min/m2 The formula for creatinine clearance (CrCl) is: UV/P x 1.73/SA Where U is the urine creatinine in mg/dL, V is urine volume in mL/min, P is plasma creatinine in mg/dL, and SA is surface area of the patient in m2. Setting up this problem, the first thing that needs to be done is to correct units. CrCl is reported in mL/min and mL/min/m2 if correcting for body surface area. 1375 mL/24 hrs is converted to 0.95 mL/min by dividing by 1440 (hours in a day times minutes in a day) and can then be entered into the formula: (100 mg/dL)(0.95mL/min)/(1.9 mg/dL) x 1.73/1.2 m2 Here, you can see the mg/dL cancel out and the units you are left with are mL/min/m2. Now, you just calculate and you will get 72 mL/min/m2.

A patient's electrolyte results are the following: Sodium = 145 mmol/L Chloride = 113 mmol/L Bicarbonate = 24 mmol/L Calculate the anion gap for this patient and choose the correct answer below. - 32 mmol/L - 8 mmol/L - 27.7 mmol/L - 3.7 mmol/L

- 8 mmol/L The anion gap, which is typically used to evaluate an instrument's analysis process, is calculated with the following formula: Anion Gap = Sodium - (Chloride + Bicarbonate) In this case, the calculation would be: Anion Gap = 145 mmol/L - (113 mmol/L + 24 mmol/L) = 8 mmol/L *Normal Range for Anion Gap = 10-20 mmol/L

Which of the following would be considered a normal cerebrospinal fluid glucose level if the serum glucose is 70 mg/dL? - About 100 mg/dL - About 45 mg/dL - About 60 mg/dL - About 70 mg/dL

- About 45 mg/dL As a general rule, CSF glucose level is about two thirds (60%-70%) of the serum glucose measured in a normal adult. For a patient with a serum glucose of 70 mg/dL, the normal CSF value would be about 45 mg/dL.

The ketone component that is measured by the nitroprusside reaction is: - Acetoacetic acid - Beta-hydroxybutyric acid - Acetone - Glycine

- Acetoacetic acid Acetoacetic acid reacts with sodium nitroprusside to produce a purple color. B-hydroxybutyrate and acetone are derived from acetoacetic acid. However, B-hydroxybutyrate is not measured and only slightly sensitive to acetone in presence of glycine.

Which one of the following usually shows a decrease during an acute phase response? - Albumin - Alpha-1 Antitrypsin - Fibrinogen - Ceruloplasmin

- Albumin Albumin is a "negative" acute phase protein since it is found in decreased levels during acute phase response. Other "negative" acute phase proteins include transferrin and transthyretin. Alpha-1-antitrypsin, fibrinogen, and ceruloplasmin are all "positive" acute phase proteins that are found in increased levels during acute phase response. Other "positive" acute phase proteins include alpha-1- acid glycoprotein, haptoglobin, C3, C4, C-reactive protein, and serum amyloid.

Which analyte measurement is used to detect early nephropathy in a diabetic patient? - Lactic acid - Albumin - Ketones - HbA1C

- Albumin The detection of small concentrations of albumin in the urine is used to detect early renal impairment. The term "microalbumin" is no longer used since "albuminuria occurs on a continuum". Diabetic patients develop over time diabetic kidney disease which may be delayed by aggressive glycemic control. An early indicator of diabetic kidney disease is the detection of albumin in the urine. It is recommended that diabetic patients be tested for albuminuria at least yearly so diabetic kidney disease can be diagnosed at a stage where it is still reversible with treatment.

A patient that is on a vegetarian diet will most likely have a(n): - Alkaline pH - Acid pH - Neutral pH - pH is not affected by diet

- Alkaline pH A patient that is on a vegetarian diet will most likely have an alkaline urine pH. Patients on high meat diets tend to have an acid urine pH.

Which of the following tests is the BEST screening test for neural tube defects? - Placental lactogen - Bilirubin - Estriol - Alpha-fetoprotein

- Alpha-fetoprotein Alpha-fetoprotein is produced by the fetal liver. It is measured in pregnant women, using maternal blood or amniotic fluid, as a screening test for a subset developmental abnormalities. Abnormally high levels of this substance is associated with defects in the fetal neural tube, while abnormally low levels are associated with the presence of Down' syndrome.

A microscopic examination of a normal urine pH 8.0 shows 2+ yellow-brown thorny spheres which are MOST probably: - Ammonium biurate crystals - Waxy casts - Amorphous urate crystals - Crenated red cells

- Ammonium biurate crystals Ammonium biurate crystals appear as yellow to brown spherical bodies with long irregular spicules, known as "thorn apples". They can occasionally be identified in the alkaline urine of healthy patients, but can also be associated with specimens that are old or not stored properly.

Which of the following choices is correct when describing the principles of competitive radioimmunoassay procedures? - Antibody will react preferentially with the labeled antigen - Antibody will react preferentially with the unlabeled antigen - Antibody will react with labeled antigen only - Antibody will react equally with labeled and unlabeled antigen

- Antibody will react equally with labeled and unlabeled antigen In radioimmunoassay, a fixed concentration of labeled antigen is incubated with a constant amount of antiserum such that the concentration of antigen-binding sites on the antibody is limiting. If an unlabeled antigen is added to this system, there is competition between labeled antigen and unlabeled antigen for the limited and constant number of binding sites on the antibody, and thus the amount of labeled antigen bound to antibody will decrease as the concentration of unlabeled antigen increases.

Carbon dioxide is predominately found in the blood in the form of: - Bound CO2 - Bicarbonate ions - Sodium carbonatep - CO2

- Bicarbonate ions In the body, most of the CO2 is in the form of a substance called bicarbonate (HCO3-). Therefore, the CO2 blood test is really a measure of your blood bicarbonate level.

Bacterial contamination of a urine specimen from a normal healthy individual could originate from all of the following except: - Contaminated urine container - Vagina - Bladder - Vulva

- Bladder Urine in the bladder is normally sterile unless an infection is present. Normal genital flora can be introduced in the collection container if the specimen is not collected appropriately (clean-catch, suprapubic aspiration, or catheterization). Most Urinary Tract Infections (UTIs) start in the lower urinary tract due to fecal contamination.

Estrogen (ERs) and progesterone (PRs) receptors used as tumor markers are most commonly employed to provide prognostic information about: - Breast cancer - Uterine cancer - Menopause - Cervical cancer

- Breast cancer ERs and PRs receptors are used as tumor markers for breast cancer. Patients with tumors positive for both estrogen and progesterone receptors tend to respond favorably to hormonal therapy, whereas those without generally do not. Patients with positive estrogen and progesterone receptors also have a somewhat better prognosis.

Ionized calcium is currently most commonly measured using which of the following method? - Flame photometry - Color complex formation between calcium and o-cresolphthalein - Atomic absorption - Calcium ion selective electrodes

- Calcium ion selective electrodes Ion Selective Electrodes, or ISEs, are the most common methodology used to detect calcium in various laboratory instruments. A calcium ISE has a PVC membrane, which is impregnated with an organic molecule that selectively binds and transports Ca++ ions, and contains an internal solution with a fixed concentration of calcium chloride - added to the KCl / AgCl solution of the internal reference system. Other methods for calcium analysis include orthocrestolphthalein complexone, arsenazo III dye, and atomic absorption spectroscopy (AAS), although they are rarely used in the clinical setting.

Identify the urine sediment elements indicated by the arrows in this microscopic field. - Calcium oxalate crystals - Uric acid crystals - Amorphous urate crystals - Cystine crystals

- Calcium oxalate crystals Calcium oxalate crystals can be seen in acid or neutral urine. They may also be present in normal urine. They characteristically occur as octahedral or envelope shapes. They can also be viewed as having a Maltese cross when one focuses up and down through the crystal. Uric acid crystals are variably shaped: they occur as flat diamond (four-sized), rhombic, lemon-shaped, or rarely hexagonal shapes with a yellowish or yellowish-brown coloration. They are present in acid urine. They are polarizable and show various colors when polarized. They may be present in normal urine. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Amorphous urates are found in acid urine and look like brick color or yellow/brown dust. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria.

Which of the following would be the most characteristic finding in synovial fluid in a case of pseudogout? - Monosodium urate crystals - Calcium pyrophosphate crystals - Macrophage infiltration - Mixed RBC/WBC infiltration

- Calcium pyrophosphate crystals Calcium pyrophosphate crystals are characteristic of pseudogout. Pseudogout is a result of endocrine disorders that produce high levels of calcium in serum. It can also be a result of degenerative arthritis producing cartilage calcification. Monosodium urate crystals are the causative agent for gout. Macrophages can be normal in synovial fluid, but large quantities may be associated with viral infections. RBCs are not usually seen and WBCs are usually seen in viral or bacterial infections. None of then cause pseudogout.

CSF lymphocytosis is associated with all of the following EXCEPT: - Cerebral abscess - Viral meningitis - Chronic fungal meningitis - Chronic tuberculous meningitis

- Cerebral abscess CSF lymphocytosis is NOT associated with cerebral abscess. Lumbar puncture to obtain CSF samples is often contraindicated in those with a suspected brain abscess. There are many causes of CSF lymphocytosis. Lymphocytosis is seen in viral, fungal, and tuberculous infections, although a predominance of neutrophils may be present in the early stages of these infections.

The fluid that surrounds and protects the spinal cord and brain is called: - Peritoneal fluid - Amniotic fluid - Cerebrospinal fluid - Pleural fluid

- Cerebrospinal fluid Cerebrospinal fluid is the fluid that surrounds and protects the spinal cord and brain. Peritoneal fluid is fluid created in the abdominal cavity. Amniotic fluid is the protective fluid found within the membranes that hold and surround an embryo or fetus. Pleural fluid is the fluid found in the cavity surrounding the lungs.

Which of the following tests would be used in the assessment of glomerular filtration? - 24 hour urine protein - Creatinine clearance - PSP test - Urea

- Creatinine clearance Creatinine excretion is related to muscle mass and is fairly constant from day to day for a given individual. Plasma concentrations of creatinine are used to assess renal function. Creatinine clearance is based on the serum creatinine level and is used to measure glomerular filtration rate, or GFR. Creatinine is filtered by the glomerulus and is not reabsorbed; therefore it can be used to estimate the GFR.

A cerebrospinal fluid sample from a possible meningitis patient demonstrated a round, budding yeast of variable size on Gram stain. The specimen was cultured to routine fungal media without cycloheximide. The organism rapidly produced urease and demonstrated brown pigmented colonies on niger seed agar. The organism identification is: - Cryptococcus neoformans - Candida albicans - Malassezia furfur - Trichosporan species

- Cryptococcus neoformans Cryptococcus neoformans is a significant human pathogen that has been associated with meningitis, pulmonary infections, and fungemia, especially in immunocompromised patients. Some of these isolates have the ability to produce a polysaccharide capsule that is visible with capsular stains or an India ink prep. The capsule may cause the colonies to be mucoid except on inhibitory mold agar. A presumptive identification may be made with a rapid positive urease test. Brown pigment colonies on niger seed agar have been sufficient for final identification. Candida albicans is a significant human pathogen as a cause of thrush, vulvovaginitis, respiratory infection, meningitis, and more. This organism produces small budding yeast with pseudohyphae and smooth, creamy, white colonies on fungal media. It produces urease but it is not rapid and it does not produce a pigment on niger seed agar. Malassezia furfur is more commonly known to cause skin infections but other infections may occur. Diagnosis is typically based on direct microscopic examination of skin scrapings. If the sample is cultured, the organism requires an over-lay with olive oil for growth. Colonies are smooth, creamy, and white but smaller than Candida albicans colonies. It does not produce brown colonies on niger seed agar. Trichosporon species cause skin infections and fungemia, especially in immunocompromised individuals. Direct examination demonstrates the presence of arthroconidia. The colonies have been described as dry, heaped, and powdery. It is also known to produce urease but it is not rapid. It does not produce brown-pigmented colonies on niger seed agar.

A 64-year old man lost 15 pounds, became weaker, and his face became fuller with a ruddy complexion. His laboratory tests revealed: Serum cortisol: 8 AM: 880 nmol/L, 138-635 nmol/L (reference range) 4 PM: 828 nmol/L, 83-414 nmol/L (reference range) After these results, an overnight dexamethasone suppression test gave a cortisol level of 773 nmol/L. The MOST probable diagnosis for this patient is: - Congenital adrenal hyperplasia - Addison's disease - Cushing's Syndrome - Conn's Syndrome

- Cushing's Syndrome Cushing's syndrome is a hormonal disorder caused by the effects of an individual having high levels of cortisol. One of the signs of this condition is skin, which becomes fragile and thin and a rounding, or fullness of the face. More than one test is performed to diagnose Cushing's syndrome and includes the 24-hour urinary free cortisol test, measurement of day and night cortisol levels, and the low-dose dexamethasone suppression test. Cortisol production is normally suppressed at night, but in Cushing's syndrome, this suppression doesn't occur. If the cortisol level is more than 50 nmol/L, Cushing's syndrome is suspected. In the dexamethasone suppression test, cortisol signals the pituitary to release less ACTH, so the normal response after taking dexamethasone is a decrease in blood and urine cortisol levels; if cortisol levels do not decrease (such as in this case), Cushing's syndrome is suspected.

What is the purpose of the BUN test? - Rules out acute heart failure in the emergency setting. - Determines the amount of urea in blood. - Evaluates abnormalities in the extrinsic coagulation pathway and monitors coumarin therapy. - Evaluates abnormalities in the intrinsic coagulation pathway and monitors heparin therapy.

- Determines the amount of urea in blood. Blood urea nitrogen (BUN) is the test used to determine the amount of urea in the blood. B-type natriuretic peptide (BNP) is a cardiac hormone released by the heart during stressful situations such as ventricular volume expansion and pressure overload. The main clinical utility of BNP is that a normal level rules out acute heart failure in the emergency setting. Prothrombin time (PT) is the test used to evaluate abnormalities in the extrinsic coagulation pathway and monitor coumarin therapy. Activated partial thromboplastin time (aPTT or PTT) is the test used to Evaluate abnormalities in the intrinsic coagulation pathway and monitor heparin therapy.

The elements indicated by the arrows are more likely to be seen in patients with which condition? - Bacterial infection - Nephrotic syndrome - Diabetes - Renal failure

- Diabetes Yeast cells as a cause of infection are more commonly found in diabetes mellitus patients but can also represent contaminants with no clinical significance. They should not be confused with erythrocytes. The presence of budding helps with the identification.

Recently the American Diabetes Association (ADA) recommended reporting which of these values in order to correlate with hemoglobin A1C (HbA1C) as a further indicator of glycemic control? - Estimated average glucose - Blood urea nitrogen - Microalbumin - Insulin

- Estimated average glucose In 2008, the ADA recommended calculating and reporting the estimated average glucose (eAG) with HbA1C measurement results. The eAG can be calculated from percent HgA1C by using the following formula: eAG (mg/dL) = 28.7 X HgA1C - 46.7 eAG HbA1C (%) 97 mg/dL 5 126 mg/dL 6 154 mg/dL 7 183 mg/dL 8 212 mg/dL 9 240 mg/dL 10 269 mg/dL 11 298 mg/dL 12

Sudan III will confirm the presence of: - Parasites - Sperm - Mucus - Fat

- Fat Sudan III is used to identify the presence of lipids or fats in laboratory samples. Oil Red O is another stain used to identify oval fat bodies in urine.

In hemoglobin synthesis, which enzyme is responsible for adding iron in the last step? - ALA Synthase - Ferrochelatase - PBG Synthase - Protoporphyrinogen oxidase

- Ferrochelatase Ferrochelatase is the enzyme responsible for adding iron into the porphyrin ring in the final step of heme synthesis. ALA synthase is the enzyme used in the first step to create delta-aminolevulinic acid (ALA); PBG synthase is used in the second step to condense two ALA molecules into porphobilinogen; protoporphyrinogen oxidase catalyzes the second to last step to create protoporphyrin.

Which of the following artifacts may be mistaken for casts? - Air bubbles - Fibers - Coverslip scratches - Talc particles

- Fibers Fibers can be mistaken for casts on occasion, especially hyaline casts. Fibers, however, are usually thinner and appear less uniform in structure than casts do. As a result, they can contaminate a urine specimen from clothing and diapers and be confused with casts by inexperienced techs. To differentiate fiber artifacts from most casts, the specimen can be examined by the tech under polarized light. This is because fibers polarize while most casts do not.

ACTH controls which step of steroid hormone production? - First step (cholesterol to cholesterol esters) - First step (cholesterol esters to cholesterol) - Second step (cholesterol to pregnenolone) - Third step (cholesterol esters to pregnenolone)

- First step (cholesterol esters to cholesterol) ACTH controls the first step of steroid hormone production, causing cholesterol esters to convert to cholesterol before the subsequent formation of other steroid hormones.

Conditions that produce elevated CSF protein levels include all of the following EXCEPT: - Meningitis - Multiple sclerosis - Hemorrhage - Fluid leak

- Fluid leak Fluid leak would result in a decreased protein level. Any condition that causes damage to the blood-brain barrier mostly likely will cause elevated protein levels in the CSF. Meningitis, multiple sclerosis, and hemorrhage would all result in elevated protein levels in the CSF.

All of the following statements about fluorometry are true, EXCEPT: - Fluorometry is more sensitive than spectrophotometry. - Both excitation and emission spectra are characteristics of the analyte. - Fluorescence is indirectly proportional to the analyte being measured. - Fluorometers typically utilize monochromators or optical filters.

- Fluorescence is indirectly proportional to the analyte being measured. The correct answer is fluorescence is indirectly proportional to the analyte being measured. A fluorometer generates the wavelength of light required to excite the analyte (fluorophore) of interest; it selectively transmits the wavelength of light emitted, then it measures the intensity of the emitted light. The emitted light is proportional to the concentration of the analyte (fluorophore) being measured (up to a maximum concentration). Monochromators or optical filters help to select the proper excitation and emission wavelengths for the testing being performed.

All of the following tests are part of the routine semen analysis, EXCEPT: - pH - Motility - Fructose level - Morphology

- Fructose level Routine semen analysis includes appearance, volume, viscosity, pH, sperm count and concentration, motility, and morphology. The Fructose test is not employed for routine seminal fluid analysis, but may be performed as a special functional test if there is a low sperm count. The seminal vesicles are the source of fructose in semen and fructose is used by the spermatozoa as an energy source.

Each of the following hypothalamic hormones is correctly matched with the anterior pituitary hormone that it releases EXCEPT: - TRH --> TSH - GnRH --> LH and FSH - CRH --> ACTH - GHRH --> Oxytocin

- GHRH --> Oxytocin GHRH (growth hormone-releasing hormone), a hypothalamic hormone, is responsible for causing GH (growth hormone), not Oxytocin, to be released by the anterior pituitary gland. Oxytocin is not a hormone that is produced by the anterior pituitary gland. Oxytocin is produced in the hypothalamus and is stored in the posterior pituitary gland. TRH (thyroid releasing hormone) is a hypothalamic hormone that acts on the anterior pituitary to release TSH (thyroid-stimulating hormone) and prolactin. GnRH (gonadotropin-releasing hormone) is a hypothalamic hormone that acts on the anterior pituitary to release LH (luteinizing hormone) and FSH (follicle-stimulating hormone).CRH (corticotropin-releasing hormone) is a hypothalamic hormone that acts on the anterior pituitary to release ACTH (adrenocorticotropic hormone).

All of the following hormones are produced primarily in the pancreatic islets EXCEPT which one? - Gastrin - Glucagon - Insulin - Pancreatic polypeptide

- Gastrin Gastrin is a hormone produced by cells primarily in the gastrointestinal tract and it stimulates the secretion of gastric acid and gastric mucosal growth. The other hormones listed are all produced by the pancreas.

Zollinger-Ellison syndrome is characterized by a large (usually 20-fold) elevation of: - Cholecystokinin - Pepsin - Glucagon - Gastrin

- Gastrin Zollinger-Ellison syndrome, or ZES, is a rare disorder where one or more tumors in the pancreas, duodenum, or intestinal lymph nodes produce gastrin, causing the parietal cells of the stomach to make too much acid (up to 20-fold), leading to multiple peptic ulcers. Cholecystokinin plays a key role in facilitating digestion within the small intestine and is not found in elevated levels in ZES. Pepsin is an enzyme that is released by the chief cells in the stomach to degrade food proteins into peptides and is not found in elevated levels in ZES. Finally, glucagon is a hormone produced by the pancreatic islet cells which raises glucose levels and counteracts the effect of insulin. It is also not associated with ZES.

All of the following parameters are generally considered to be a part of seminal fluid analysis, EXCEPT? - Sperm count and motility - Morphology examination - Viscosity assessment - Glucose concentration

- Glucose concentration Glucose concentrations are not performed during semen analysis procedures. However, sperm count, morphologic examinations, viscosity assessments, motility, appearance, volume, and pH, assessments are usually included in a semen analysis procedure.

A major action of angiotensin 2 is: - Increased pituitary secretion of petressin - Increased vasoconstriction - Increased parathormone secretion by the parathyroid - Decreased adrenal secretion of aldosterone

- Increased vasoconstriction Angiotensin 2 is an oligopeptide in the blood that causes vasoconstriction of arterioles, increased blood pressure, and release of aldosterone from zona glomerulosa of the adrenals. Aldosterone in turn induces sodium retention in the collection ducts of the kidney, subsequently conserving water and increasing vascular volume.

Which of the following tests on amniotic fluid would be included when assessing fetal lung maturity: - Alpha Fetoprotein - Bilirubin - L/S Ratio - Fetal hemoglobin

- L/S Ratio The correct answer choice here is L/S ratio. The lecithin/sphingomyelin ratio is determined by examining the amniotic fluid of a pregnant mother. Because amniotic fluid is continuously swallowed or inhaled and then replaced or exhaled in uterus the ratio can be measured to determine how much surfactant is in the fetal lungs. This ratio will help determine how well the infant's lungs will perform breathing at birth. Alpha-fetoprotein is used in assessing the potential for genetic disorders. Bilirubin is used in diagnosing the cause of jaundice and other liver problems. Fetal hemoglobin is not used to assess fetal lung maturity.

With the development of fetal lung maturity, which of the following phospholipid concentrations in amniotic fluid increases? - Sphingomyelin - Phosphatidyl ethanolamine - Phosphatidylinositol - Lecithin

- Lecithin When testing for fetal lung maturity, often the L/S ratio is determined. The L in the L/S ratio stands for Lecithin, which is one of the pulmonary surfactants needed to reduce the surface tension of the air-liquid interface of the alveolar lining, so that alveoli don't collapse upon expiration. The S stands for sphingomyelin, another pulmonary surfactant. Until about 32-33 weeks of gestation, the concentration of these two substances are quite similar; thereafter the concentration of lecithin increases significantly compared with the relatively constant concentration of sphingomyelin. In the absence of complications, the ratio of these two components reaches 2.0 at about 35 weeks gestation. Infants delivered after attaining an L/S ratio of 2.0 or higher rarely develop respiratory distress syndrome (RDS). This value of 2.0 has become the commonly accepted standard value indicating maturity in the fetus of a non-diabetic woman.

Which medication is primarily used in the treatment of bipolar disorder? - Lithium - Imipramine - Amitriptyline - Doxepin

- Lithium Lithium is a mood-altering drug primarily used in the treatment of bipolar disorder, recurrent depression, and aggressive or self-mutilating behavior though it may also be used as a preventative treatment for migraines and cluster headaches. Tricyclic antidepressants are a class of drugs used to treat depression, insomnia, extreme apathy, and loss of libido. From a clinical laboratory perspective, imipramine, amitriptyline, and doxepin are the most relevant.

All of the following are primary functions of the kidney, EXCEPT? - Acid-base balance - Retention of essential nutrients and water - Reabsorption of waste products - Blood filtration

- Reabsorption of waste products Blood is filtered in the kidney, nutrients, water, and salts are reabsorbed while waste products are eliminated from the body by the urinary system. The kidney also helps regulate the acid-base balance in the body.

A patient with an infectious mononucleosis infection presents in the emergency room. Physicians order a spinal tap, which is immediately sent to the laboratory for review. What is the cell in the image below from this patient's cerebrospinal fluid sample? - Reactive Lymphocyte - Monocyte - Macrophage - Mesothelial Cell

- Reactive Lymphocyte The cell depicted with the arrow in this image is an atypical (reactive) lymphocyte. These cells are commonly found in certain viral infections, especially infectious mononucleosis. Notice the larger size and abundant cytoplasm present in this lymphocyte. There is also apparent vacuolization, which is a key feature of atypical lymphocytes. The chromatin pattern of this cell, as well as the overall shape, color, and size, rules out the monocyte, macrophage, and mesothelial cell choices.

On a patient that has a large amount of glucose in their urine, what would be the expected specific gravity (SG) taken from a refractometer in comparison to the dipstick SG? - Refractometer SG would be lower than dipstick SG. - Refractometer SG would be higher than Dipstick SG. - Dipstick SG would be the same as refractometer SG. - Unable to determine.

- Refractometer SG would be higher than Dipstick SG. The reagent strip (dipstick) SG only measures ionic solutes and does not detect organic molecules such as glucose and urea. In this question, because of the large amount of glucose detected in the urine, we would expect the refractometer SG to be higher than that of the dipstick SG. Radiographic contrast material and plasma expanders may also cause an increased SG by the refractometer method.

You are processing specimens for your laboratory when you receive a potassium test specimen in a tube that looks like the one in the image. What should you do? - Accept the specimen, the potassium test results will not be affected. - Reject the specimen, the potassium test results will be decreased. - Reject the specimen, the potassium test results will be increased. - Re-centrifuge the specimen, the first time it was not done properly.

- Reject the specimen, the potassium test results will be increased. The specimen in the image is grossly hemolyzed. Hemolysis occurs when red blood cells break down, releasing their contents into the plasma. Potassium is located mostly inside the red blood cells, so that rupture of the cell membrane would result in a significant increase in plasma potassium. A grossly hemolyzed specimen will produce an inaccurate patient potassium result and should be rejected for testing. Re-centrifuging the specimen will not resolve the hemolysis, it will actually hemolyze the blood even more.

Which of the following cells when found upon microscopic examination of the urine would be most indicative of kidney disease: - WBCs and bacteria - Renal tubular epithelial cells - Squamous epithelial cells - RBCs

- Renal tubular epithelial cells Renal tubular epithelial cells are frequently seen in patients with acute renal tubular necrosis. They are most easily recognized when they form casts. WBCs and bacteria may be indicative of a urinary tract infection. Squamous epithelial cells are the largest cells found in urine sediment and are normally shed from the lower linings of the urethra. They typically do not have clinical significance. RBCs are seen due to vascular injury within the GI tract or due to damage to the glomerular membrane.

The Lecithin/Sphingomyelin (L/S) ratio determination of amniotic fluid is useful in assessing the probability of: - Cystic fibrosis - Phenylketonuria - Respiratory distress syndrome - Chromosomal abnormalities

- Respiratory distress syndrome The lecithin-sphingomyelin ratio is a test for assessing fetal lung maturity that is useful in determining risk of an infant born with respiratory distress syndrome. L/S ratio <2.0 indicates an increased risk of respiratory distress syndrome (RDS) at delivery. L/S ratio <1.5 indicates a very high risk of developing RDS. Until about 32-33 weeks of gestation, the concentration of these two substances are quite similar; thereafter the concentration of lecithin increases significantly compared with the relatively constant concentration of sphingomyelin. In the absence of complications, the ratio of these two components reaches 2.0 at about 35 weeks gestation. Infants delivered after attaining an L/S ratio of 2.0 or higher rarely develop respiratory distress syndrome (RDS). This value of 2.0 has become the commonly accepted standard value indicating maturity in the fetus of a non-diabetic woman.

At what temperature should the urine be prior to testing with the reagent strip method? - 4 C - 37 C - Room temperature - Temperature does not affect test results

- Room temperature Urine should be at room temperature prior to testing with the reagent strip method. Urine strip reactivity can increase with increased urine temperature, so the optimum temperature is 22-26oC or room temperature.

A patient is seen in the ER for abdominal pain and jaundice (yellowing of the skin and sclera). A quick urinalysis is performed, and it is noted there is an increase in urine urobilinogen. All of the following are likely causes EXCEPT: - Hepatitis - Hemolytic episode - Cholelithiasis - Chronic liver disease

- Cholelithiasis Out of the four choices, all would cause an increase in urinary urobilinogen except cholelithiasis, or gallstones, which would cause a decreased or absent urinary urobilinogen. An event that increases the bilirubin levels (hemolysis), or a liver disease (hepatitis/chronic liver disease) that disrupts the liver's ability to reabsorb urobilinogen for fecal excretion, will cause an increase in the amount of urobilinogen in the blood that is excreted by the kidneys.

Identify the crystals in the image. - Leucine crystals - Cholesterol crystals - Bilirubin crystals - Cystine crystals

- Cholesterol crystals These are cholesterol crystals. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. Leucine crystals are associated with liver disease. They are found in acid to neutral pH urine specimens and are yellow in color. Concentric circles and radial striations are noted microscopically. Bilirubin crystals are yellow, needle-like crystals that may appear in clumps. They are found in acid urine and are associated with liver disease. Cystine crystals are present in acidic urine, are typically colorless, and have characteristic hexagonal shapes. These crystals are associated with cystinuria.

Which of the following areas of the brain and spinal cord is responsible for producing CSF? - Subarachnoid space - Dura mater - Choroid plexuses - Arachnoid granulations

- Choroid plexuses CSF is produced in the choroid plexuses of the two lumbar ventricles and the third and fourth ventricles. CSF flows through the subarachnoid space but it is not produced there. The dura mater is part of the meninges which line the brain and spinal cord. CSF is reabsorbed back in the blood capillaries in the arachnoid granulations.

The accuracy of an immunoassay is its ability to discriminate between results that are true positive and results that are true negative. Two parameters of test accuracy are specificity and sensitivity. Which of these statements apply to an immunoassay with low sensitivity? - Accurately identifies the presence of disease - Has few false-negative results - Has many false-negative results - Accurately detects the absence of disease

- Has many false-negative results A test with high specificity accurately detects the absence of disease. The more specific a test is, the fewer false-positive results will occur. A test with high sensitivity accurately identifies the presence of disease. The more sensitive a test, the fewer false-negative results it produces. In the case stated in this question, the test has low sensitivity, so it may not identify all individuals who actually have the disease; it may produce many false-negative results.

When considering therapeutic drug monitoring, which two organ systems are associated with drug elimination? - Cardiac and pulmonary - Hepatic and renal - Renal and cardiac - Hepatic and respiratory

- Hepatic and renal The hepatic and renal systems are associated with drug elimination. Hepatic disease states characterized by a loss of functional tissue may result in slower rates of clearance and corresponding longer drug half-life. The plasma-free fraction of a parent drug or its metabolites is subject to glomerular filtration, renal secretion, or both. Therapeutic drugs may involve the heart (e.g. digoxin) or the lungs (e.g. theophylline), but those organ systems are not involved in the elimination of the drugs.

Where are most acute phase proteins synthesized? - Bone Marrow - Hepatocytes - Intestines - Spleen

- Hepatocytes Most acute phase proteins are produced in the liver by hepatocytes in response to tissue damage or inflammation. Bone marrow, intestines, and spleen do not synthesize acute-phase proteins.

A high-sensitivity C-reactive protein (hs-CRP) test result of 5 mg/L (normal = < 1 mg/L) may indicate which of the following? - Low risk for cardiovascular disease (CVD) - High risk for future CVD - Acute inflammatory condition - No risk for future CVD

- High risk for future CVD High-sensitivity C-reactive protein (hs-CRP) is used as an aid in the diagnosis and treatment of cardiovascular disease (CVD). At low levels, it can detect those at risk for cardiac heart disease. At high levels in those with no history of heart disease, it indicates a high risk for acute myocardial infarction (AMI), stroke, or peripheral vascular disease. For patients with acute coronary syndrome (ACS) or stable coronary disease, hs-CRP is used to predict future coronary events. Ranges of hs-CRP in the prediction of risk for CVD are: - <1.0 mg/L Low CVD risk - 1.0-3.0 mg/L Average risk for CVD - >3.0 mg/L High risk for future CVD If results are >10.0 mg/L, the patient should be evaluated for an acute inflammatory condition.

Which of the following may be associated with acidic urinary pH? - Metabolic alkalosis - Renal tubular acidosis - Vegetarian diet - High urine glucose

- High urine glucose Diabetes mellitus can cause acidic urine after controlling for dietary factors. Metabolic alkalosis will cause the urine to be alkaline. Loss of excessive electrolytes in consistent vomiting could be one of the factors. Renal tubular acidosis occurs when impaired kidneys function can't maintain acid-base balance which can lead to failure in excreting acid in the urine and reabsorbing bicarbonate. A diet high in citrus fruits and vegetables raises the pH and produces alkaline urine.

Which of the following is the most common technique that is used by clinical laboratories for therapeutic drug monitoring? - Immunoassay - Electrophoresis - Atomic absorption - Ion-selective electrode voltametry

- Immunoassay Immunoassay is the most common technique that is used by clinical laboratories for therapeutic drug monitoring (TDM). Most of the drugs commonly assessed with TDM can be measured on analytical platforms which utilize antibodies (in some form) for detection. Antibodies can be developed that recognize drugs. Although most drugs are much too small to evoke an immune response, scientists can conjugate drugs to immunogenic proteins to produce antibodies that recognize drug-specific epitopes.

All of the following conditions are associated with a polyclonal (broadbased) increase in gamma globulins except? - Liver disease - Chronic inflammation - Immune reaction - Immunodeficiency

- Immunodeficiency Immunodeficiency would, of course, generally be associated with a decrease in serum immunoglobulin levels, and an associated decreased gamma band. Polyclonal increases are associated with infection, inflammation, liver disease, rheumatoid diseases, and lymphoproliferative disorders.

Which of the following tests confirms the presence of Bence-Jones proteinuria: - Protein electrophoresis - Sulfosalicylic acid precipitation - Cryoprecipitation - Immunoelectrophoresis

- Immunoelectrophoresis Immunoelectrophoresis is used to detect the presence of Bence-Jones proteins. Immunoelectrophoresis is used to help detect, diagnose, and monitor the course and treatment of conditions associated with abnormal proteins (such as Bence-Jones), including Multiple Myeloma, Waldenstrom's macroglobulinemia, and a few other related diseases.

Which of the following is considered an action of the hormone glucagon? - Increase glycogenolysis - Increase glycogenesis - Increase glycolysis - Increase lipogenesis

- Increase glycogenolysis Glucagon is the primary hormone responsible for increasing glucose levels in the blood. Glucagon increases plasma glucose levels by increasing glycogenolysis (breakdown of glycogen to glucose) and increasing gluconeogenesis (formation of glucose-6-phosphate from non-carbohydrate sources). Insulin is the primary hormone responsible for the entry of glucose into the cell. The release of insulin causes an increase in glycogenesis (conversion of glucose to glycogen for storage), an increase in glycolysis (metabolism of a glucose molecule to pyruvate or lactate for production of energy), and an increase in lipogenesis (conversion of carbohydrates to fatty acids).

The image on the right is a cytospin preparation of cerebrospinal fluid viewed at 1000X magnification. What is the identity of the primary blood cell type observed in this microscopic field? - Monocytes - Macrophages - Mesothelial cells - Lymphocytes

- Lymphocytes This is the normal range of variation for lymphocytes in a cytospin. There are no monocytes, macrophages, or mesothelial cells present in this image. Lymphocytes typically have condensed chromatin and scant blue cytoplasm. Small numbers are normal, but Increased numbers can be associated with viral infections, meningitis, and others. Monocytes are large cells, often with convoluted nuclei and large cytoplasms, and are infrequently seen in CSF. Sometimes they can be seen in meningitis or other conditions. Macrophages are not seen in normal CSF but can be seen in meningitis and other conditions. They are large cells with abundant cytoplasm. Mesothelial cells are not found in normal CSF. If present, the distinction from macrophages is sometimes difficult.

Normal adult CSF may have 0-5 white blood cells (WBCs)/µL. Which of the following cell types account for 60-100% of these WBCs? - Neutrophils - Lymphocytes - Monocytes - Eosinophils

- Lymphocytes Typically, majority of cells seen in a normal adult CSF specimen are lymphocytes and monocytes (70:30 ratio). This ratio is reversed in children.

Myoglobinuria is MOST likely to be noted in urine specimens from patients with which of the following disorders? - Hemolytic anemia - Lower urinary tract infections - Massive muscle trauma - Paroxysmal nocturnal hemoglobinuria

- Massive muscle trauma Myoglobinuria is a condition in which myoglobin (heme-containing protein in muscle) is found in urine due to muscle destruction. It produces a clear red-brown urine. Myoglobin release is strongly associated with muscle damage; therefore, it would most closely match a diagnosis of massive muscle trauma in this question.

The image is a stained smear of cerebrospinal fluid. The cell in this slide could be caused by what condition? - Viral meningitis - Allergic reaction - Cerebral hemorrhage - Metastasis

- Metastasis The nucleus in this cell is abnormal and appears to have divided. This finding correlates with the presence of metastasis in the CSF. A broad spectrum of lymphocytes and monocytes would be present in a case of viral meningitis. An allergic reaction will show predominantly eosinophils. Cerebral hemorrhage would show predominantly RBCs.

Creatinine excretion correlates best with which of the following parameters: - Age - Sex - Muscle mass - Bodyweight

- Muscle mass Creatinine excretion is related to muscle mass and is fairly constant from day to day for a given individual. Plasma concentrations of creatinine are used to assess renal function. Creatinine clearance is based on the serum creatinine level and is used to measure glomerular filtration rate or GFR.

All of the following conditions produce glycosuria, EXCEPT? - Diabetes mellitus - Fanconi's syndrome - Impaired tubular reabsorption/advanced kidney failure - Myocardial infarction

- Myocardial infarction Diabetes mellitus, Fanconi's syndrome, and impaired tubular reabsorption/advanced kidney failure can cause glycosuria, myocardial infarction does not. Glycosuria is defined as the presence of glucose in the urine. It most commonly results from diabetes mellitus and impaired tubular reabsorption, but may also occur in Fanconi's syndrome, pregnancy, and in patients taking adrenocorticosteroids among other conditions.

When testing for ethanol, what is actually measured in the enzymatic reaction, that is proportional to ethanol concentration? - NADH - Acetaldehyde - Acetone - NAD

- NADH When testing for ethanol by the enzymatic method, the amount of NADH produced is measured and proportional to the amount of ethanol in the sample. Acetaldehyde is the breakdown product of ethanol but is not used for measurements; acetone is not a breakdown product of ethanol nor used for ethanol measurement; NAD is the cofactor used in ethanol determinations but the reduced form of NADH is used for measurement.

Proteins in a buffer that sets the pH at 8.6 will become ___________ charged and migrate to the ____________. - Negatively; Anode - Negatively; Cathode - Positively; Anode - Positively; Cathode

- Negatively; Anode The isoelectric point (pI) of most proteins is between pH 4.0 and 7.5. A molecule in a solution above its pI will take on a negative charge. Negatively charged molecules in an electric field will migrate to the positive electrode, the anode.

How is valproic acid (Depakote) administered? - IM injection - Sublingual - Oral preparation - IV

- Oral preparation The correct answer is oral preparation as the gastrointestinal tract completely and rapidly absorbs valproic acid, so other delivery methods are not as useful for therapy.

Which of the following statements regarding peak level in therapeutic drug monitoring is true? - Peak level is the point at which the drug is lowest in the patient's body. - Peak level is assessed by collecting a blood sample right before the next dose of the drug is given. - Peak level is the point at which the drug is highest in the patient's body. - Peak level is assessed by collecting a urine sample right after the next dose of the drug is given.

- Peak level is the point at which the drug is highest in the patient's body. The lowest level of the drug in the patient's body is called the trough level. The peak for a drug is when the level of the drug in the patient's body is the highest. To assess drug concentrations during the trough phase, blood should be drawn immediately before the next dose. To assess peak levels, the time for drawing depends on the route of administration: - Intravenous (IV): 15 - 30 minutes after injection/infusion - Intramuscular (IM): 30 minutes - one hour after injection - Oral: One hour after drug is taken (assumes a half-life of > two hours)

Bence-Jones proteinuria is associated with all of the following conditions EXCEPT: - Macroglobulinemia - Pernicious anemia - Multiple myeloma - Amyloidosis

- Pernicious anemia Macroglobulinemia, multiple myeloma, and amyloidosis are all associated with abnormal protein production and/or accumulation which can result in Bence-Jones proteins being excreted in the urine. Bence-Jones proteins are monoclonal light chains excreted in the urine, seen with multiple myeloma, and other neoplasms of lymphoid cells. Small amounts can be missed by urine dipsticks, which are more sensitive to albumin than globulins. They are best detected by urine protein electrophoresis, immunoelectrophoresis, or immunofixation. Large amounts cause renal tubular damage, resulting in myeloma kidney. Bence-Jones proteins have unusual heat solubility properties, in that they precipitate between 50 - 60 °C and redissolve at 90 - 100 °C. Historical detection methods often utilized this unusual property. Pernicious anemia is a vitamin B12 deficiency due to the lack of gastric intrinsic factor, which is, in turn, a result of autoimmune gastritis.

Of the following, which has the longest half-life? - Carbamazepine - Valproic Acid - Phenytoin - Phenobarbital

- Phenobarbital The correct answer is Phenobarbital, which has a half-life of 70-100 hours. Carbamazepine: 4-8 hours; Valproic Acid: 11-17 hours; Phenytoin: 6-24 hours. These medications are anticonvulsants that treat different types of seizure disorders, depending on the type and the patient. Phenobarbital is a slow-acting medication that is slowly absorbed and metabolized by both the liver and kidneys. Carbamazepine has a high degree of variability with absorption and more toxic side effects than the others, so it is usually prescribed when patients do not respond to other medications. The gastrointestinal tract rapidly absorbs valproic acid is eliminated by the liver. Phenytoin, while an anti-convulsant, is also used as prophylaxis in traumatic brain injuries to prevent functional loss of tissue; the liver metabolizes it.

Follicle-stimulating hormone (FSH) is produced by: - Adrenal cortex - Adrenal medulla - Pituitary - Thyroid

- Pituitary The pituitary gland produces FSH. The adrenal cortex produces corticosteroid hormones, androgens, aldosterone, etc. The adrenal medulla produces catecholamines such as epinephrine and norepinephrine. The thyroid gland produces thyroid hormones such as T3 and T4.

Parasites that can be found in urinary sediment include all of the following EXCEPT: - Enterobius vermicularis - Trichomonas vaginalis - Plasmodium malariae - Schistosoma haematobium

- Plasmodium malariae Plasmodium malariae is the only parasite that is listed that could NOT potentially be seen in urine sediment. Plasmodium is a blood parasite. Both Enterobius vermicularis and Trichomonas vaginalis could potentially arrive in the urine as contaminants from other sources; Enterobius from fecal contamination and Trichomonas from vaginal secretions. Of the parasites that are listed, only Schistosoma haematobium is a true urinary tract parasite.

A urine specimen which was collected in a dark container, stored in the dark, has a pH of 7.5, and whose sample aliquot is wrapped in foil, is most likely being sent for: - Aldosterone - Porphyrins - Catecholamines - Metanephrines

- Porphyrins Porphyrins are unstable when exposed to light. Urine specimens for porphyrin testing have to be collected in dark containers and stored away from light. Porphyrin concentrations can decrease as much as 50% if the specimens are exposed to light for 24 hours. An early morning specimen collected without preservatives and tested right away is the preferred method. If testing is delayed, the specimen should be stored in the dark for up to 48 hours at 4° C, or kept frozen at -20° C for at least a month.

Cholesterol is used by the body for which of the following functions? - Carrying dietary triglycerides to the cells through the blood - Maintaining acid-base balance - Precursor of hormone synthesis - Major source of fuel for the body

- Precursor of hormone synthesis Cholesterol is a precursor of hormone synthesis. It is not a major source of fuel itself, but does facilitate triglyceride transport to serve the fuel needs of the body. Chylomicrons carry dietary triglycerides to the cells. Bicarbonate helps to maintain acid-base balance.

Which of the following statements is true for the reagent strip procedure? - Prolonged immersion may wash out reagents. - Blot the reagent strip with a paper towel before placing it on the tray of the dipstick reader. - All tests require the same reading times. - The expiration date on the reagent strip container does not matter, as long as the controls are acceptable.

- Prolonged immersion may wash out reagents. Prolonged immersion of the strip in the specimen may wash out reagents and affect test results. Some tests on the reagent strip require specified reading times. If you are visually reading the results, it is important to adhere to the timing recommended by the reagent strip manufacturer. The edge of the strip should be run along the lip of the specimen container or touched to absorbent toweling, but should not be blotted with a paper towel. Expiration dates indicate the ensured reactivity of the reagent strips. Even though controls may be accurate, it does not guarantee that patient results will be accurate if the reagents are beyond the assigned expiration date.

Which one of the following statements about lead poisoning is false? - While lead distributes to all tissues, the central nervous system, kidney, and bone marrow are particularly susceptible to lead toxicity - Whole blood lead measurement is the best test for detecting lead toxicity - Serum lead level is a good inexpensive screening test for lead toxicity - Lead levels below 5 µg/dL in children do not prompt ongoing monitoring

- Serum lead level is a good inexpensive screening test for lead toxicity Lead is a metal commonly found in the environment which can be very toxic. The use of lead varies widely in our society and until the 1970s not much attention was given to its toxicity, especially on the growth and development in children. Leaded gasoline, lead pipes, and lead paints have been removed from use in order to decrease human exposure. While lead distributes to all tissues, the central nervous system, kidney, and bone marrow are particularly susceptible to lead toxicity. Serum lead levels are of little value, since they fluctuate rapidly, and do not remain positive very long after episodes of exposure to lead. Whole blood lead measurement is the best test for detecting lead toxicity. The CDC recommends to monitor lead levels and if the upper limit is above 5 µg/dL in children to prompt ongoing monitoring. The goal is to keep levels below 10 µg/dL in children.

Normal fecal specimens contain all of the following, EXCEPT: - Escherichia coli - Electrolytes - Urobilin - Shigella spp.

- Shigella spp. The gastrointestinal tract contains resident microbiota in the Enterobacteriaceae family that may be identified in fecal specimens, such as E. coli. However, true pathogens are not normally present, including Salmonella enterica, Shigella, and Yersinia species. Electrolytes and urobilin are normally found in feces.

Identify the urine sediment element shown by the arrow: - Budding yeast - Cylindroids - Trichomonas - Spermatozoa

- Spermatozoa Spermatozoa cells have an oval head (body) and a long, thin tail, as see in the image. It is not uncommon to see spermatozoa in the urine of men due to nocturnal emissions, after epileptic convulsions, after coitus, and due to diseases of the genital organ. Yeast cells can appear very similar to red blood cells in the urine at times. However, yeast cells are usually oval and smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. In addition, acetic acid can be added to urine samples to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. A cylindroid resembles a cast, with the exception that one end tapers out. Therefore, they are considered to have the same significance as casts. Trichomonas is the most common parasite found in urine. It is often the result of vaginal contamination. It is often mistaken for a white blood cell because of its size. However, characteristic motility (trichomonas is a flagellate organism) will help in its identification.

All of the following statements are true regarding urinalysis reagent strips EXCEPT? - Prolonged immersion may wash out reagents. - Strips should be stored to prevent exposure to moisture. - Some tests require specified reading times. - The expiration date on the bottle does not matter, as long as the controls are acceptable.

- The expiration date on the bottle does not matter, as long as the controls are acceptable. The expiration date for any reagent used in the clinical laboratory always matters. It is never acceptable to use a urinalysis dipstick that is expired. Expiration dates should be check daily as part of quality control to ensure that patients are not tested with expired reagent strips. Prolonged immersion in the urine specimen may wash out reagents rendering erroneous results. To maintain reagent viability, strips should be stored in a way that prevents exposure to moisture. Most manufacturers include a desiccant in the container to absorb any moisture that could render the strips inactive. Various test results on the reagent strip are to be read at different times. Manufacturer's recommendations should always be followed.

What is catheterization? - The surgical removal of the breast and lymph nodes around it. - The loss of consciousness resulting from insufficient blood flow to the brain. - The accumulation of interstitial fluid under the skin causing swelling. - The insertion of a tube into a patient's bladder via the urethra to aid in urination.

- The insertion of a tube into a patient's bladder via the urethra to aid in urination. The insertion of a tube into a patient's bladder via the urethra to aid in urination is called catheterization. Mastectomy is the surgical removal of the breast and lymph nodes around it. Blood collection should be avoided from the side where a mastectomy was performed due to the obstruction or stoppage of normal lymph flow (lymphostasis). Lymphostasis could change the composition of the blood, therefore creating invalid test results. The loss of consciousness resulting from insufficient blood flow to the brain is called syncope and is also known as fainting. The accumulation of interstitial fluid under the skin causing swelling is called edema. An edematous site should be avoided for venipuncture because the specimen obtained may be contaminated with interstitial fluid.

What is the purpose of the sweat chloride test? - Is a noninvasive way to collect and test for DNA. - To aid in the diagnosis of streptococcal infections. - To help diagnose peptic ulcers due to Helicobacter pylori. - To help diagnose cystic fibrosis.

- To help diagnose cystic fibrosis. The sweat chloride test is considered the golden standard for the diagnosis of cystic fibrosis. It collects sweat from the patient and tests for the chloride concentration which can be up to five times higher for cystic fibrosis patients. Buccal swabs are a noninvasive way used to collect DNA samples for testing. Throat swabs are used to collect and test for the presence of streptococcal (strep) infections. There are usually two swabs rubbed together on the back of the patient's throat. One swab is used for the rapid strep test and the other is sent to the microbiology laboratory for culture. The diagnosis of peptic ulcers caused by Helicobacter pylori is done by collecting a breath sample and testing for urease, an enzyme that breaks down urea. Urease is not normally found in the stomach.

A serum specimen for potassium testing is collected in a red top tube without a gel separator barrier. If testing is delayed by a few hours, how should the specimen be handled? - Discard the specimen and recollect right before testing is available again. - Discard the specimen and recollect in a gel separator tube. - The specimen should be centrifuged as soon as it clotted and serum should be transferred to another tube. - There is no special handling procedure for this specimen.

- The specimen should be centrifuged as soon as it clotted and serum should be transferred to another tube. Prolonged contact of serum with red blood cells can alter the results of some tests that use a serum sample. A potassium result could be significantly increased depending on the length of time that the serum remained in contact with the blood cells. The majority of potassium in the blood is contained within red cells. Continued contact with the red blood cells would allow potassium from the cells to leak into the serum portion. A gel barrier would prevent this contact, but if this type of tube is not used, the serum must be removed from the cells and transferred to another tube. The specimen can still be used and should not be discarded even though it was not collected into a gel barrier tube. It is crucial to the accuracy of the test that the serum is removed as soon as centrifugation is completed.

Which of the following may cause a false-positive protein reading on a urinalysis dipstick? - Urine pH is between 5.0 and 6.0. - The specimen has been refrigerated. - The urine specimen is highly pigmented. - A urine specimen with low specific gravity.

- The urine specimen is highly pigmented. Urine specimens that are highly pigmented may result in a false-positive protein result. Freshly voided urine should be slightly acidic (pH between 5.0 and 6.0). Acidic urine will not interfere with the protein test. However, a highly buffered alkaline urine may cause a false-positive protein reading by overriding the acid buffer that is part of the protein reagent pad. A refrigerated specimen will not cause a false-positive protein result. It is, however, best practice to allow the urine to warm up to room temperature before testing. A false-positive protein result may occur in samples with high specific gravity, not a low specific gravity.

Which of the following is the most common cause of hyperkalemia in hospitalized patients? - Cellular injury - Therapeutic potassium replacement - Chemotherapy - Leukemia

- Therapeutic potassium replacement Hyperkalemia is a condition with higher than normal levels of potassium in the serum. The most common cause of hyperkalemia in hospitalized patients is due to therapeutic potassium administration. The risk is greatest with intravenous potassium replacement. Cellular injury, chemotherapy, and leukemia can all cause hyperkalemia through a cellular shift.

A physician calls the lab to order a Hepatitis A IgG test but cannot find the code. What do you tell the physician? - There are no IgG-only tests for Hepatitis A, only a total with/without reflex to IgM - Which IgG test are you looking for: surface antigen, envelope, or core IgG? - It depends on where the patient is coming back from with travel history. - We only have tests for antigens not antibodies for IgG

- There are no IgG-only tests for Hepatitis A, only a total with/without reflex to IgM The correct answer is There are no IgG-only tests for Hepatitis A, only a total with/without reflex to IgM. This is because an IgG test only tests for exposure to the virus and cannot determine current or past infection. If a physician is looking for a current infection, an IgM test should be ordered. Normally, a total Hep A antibody test will be performed and, if positive, will reflex to IgM to look specifically for current infection. Testing does not differentiate specifically IgG from IgM. There are no antigens tests for Hepatitis A, specific antibodies to parts of the virus-like with testing for Hepatitis B, and it does not depend on where the patient is coming back from. There is, however, a stool antigen test for Hepatitis A as the viral particles are shed in the feces but are not found once liver enzymes reach their peak.

All of the following are characteristics of cast, EXCEPT? - They are cylindrical bodies. - They are formed either in the distal convoluted tubules or the collecting ducts of the kidney. - They contain Tamm-Horsfall mucoprotein. - They are formed in the urethra.

- They are formed in the urethra. Casts are cylindrical bodies formed either in the distal convoluted tubules or the collecting ducts of the kidney, not the urethra.The matrix of all casts is thought to be Tamm-Horsfall protein, a glycoprotein secreted by the distal loop of Henle and the distal tubule. This protein entraps cells and granular material of tubular origin. After formation, casts are loosened from the tubules and discharged into the urine. Casts, if present, are visible in freshly voided urine.

A urine concentration test was performed on a patient after a fluid intake deprivation period with the following findings: After 12 hours Urine Osmolality = 850 mOsm/Kg After 16 hours Urine Osmolality = 850 mOsm/Kg What do these results indicate? - This represents normal kidney function. - This represents a loss of tubular function and concentrating ability. - This represents a laboratory error, as these results are not medically possible. - These results represent end-stage renal disease.

- This represents normal kidney function. A urine osmolality of 800 mOsm or higher is considered normal when patients were deprived of fluid for 12 hrs. A concentration test is used to determine the ability of the tubules to reabsorb the essential salt and water that have been non-selectively filtered by the glomerulus. The loss of tubular reabsorption capability is often the first function affected in renal disease.

How is the majority of urobilinogen that is produced daily removed from the body? - Through urine excretion - Through sweat - Through saliva - Through fecal excretion

- Through fecal excretion The majority (about 80%) of urobilinogen that is produced daily is broken down further to urobilin in the intestines and excreted in the feces; this is what gives stool its color. The remaining 20% is reabsorbed and recirculated, with some elimination by the kidneys. Urobilinogen is not excreted in saliva or sweat.

Mrs. Jones, a diabetic, is admitted to the hospital on November 25th. It appears that she has had an acute myocardial infarction (AMI), but did not feel the severe chest pain because of diabetic neuropathy. She has not felt well since November 20th and her physician believes she possibly had an AMI on November 20th. Assuming that the infarct was uncomplicated, which of the following cardiac biomarkers would most likely still be elevated and would assist in an AMI diagnosis? - Myoglobin - Creatine kinase MB (CK-MB) - Troponin T - Insulin

- Troponin T Troponin T remains elevated after an AMI for 8-21 days, with an initial elevation within 3-12 hours after onset of myocardial necrosis. Myoglobin returns to normal range within 24-36 hours and CK-MB is back to normal range in 48-96 hours, so neither could be used in this case. Insulin is not a cardiac biomarker, is a peptide hormone produced by beta cells of the pancreatic islets and regulates the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood into liver, fat, and skeletal muscle cells.

Which of the following statements regarding trough level in therapeutic drug monitoring is true? - Trough level is assessed by collecting a blood sample after a dose of the drug is given (at a specified time). - Trough level is the point at which the drug is highest in the patient's body. - Trough level is the point at which the drug is lowest in the patient's body. - Trough level is assessed by collecting a urine sample right after the next dose of the drug is given.

- Trough level is the point at which the drug is lowest in the patient's body. - The lowest level of the drug in the patient's body is called the trough level. The peak for a drug is when the level of the drug in the patient's body is the highest. To assess drug concentrations during the trough phase, blood should be drawn immediately before the next dose. To assess peak levels, the time for drawing depends on the route of administration: - Intravenous (IV): 15 - 30 minutes after injection/infusion - Intramuscular (IM): 30 minutes - one hour after injection - Oral: One hour after drug is taken (assumes a half-life of > two hours)

Which of the following methods would be used to confirm the presence of Bence-Jones protein in the urine: - Urine protein electrophoresis or immunoelectrophoresis - Benedict qualitative test - Ictotest - Watson-Schwartz test

- Urine protein electrophoresis or immunoelectrophoresis Either protein electrophoresis or immunoelectrophoresis can be used to confirm Bence-Jones proteinuria. Benedict test is used for detecting glycosuria. The Ictotest is used for detecting urine bilirubin. Watson-Schwarz test is used in the detection of porphobilinogen and urobilinogen.

Which of the following tests included on a urine reagent strip would never be reported out as negative? - Urobilinogen - Bilirubin - Leukocyte esterase - Nitrite

- Urobilinogen Urobilinogen is reported as normal, not negative. A normal urobilinogen result is approximately: 0.2-1.0 Ehr U/dL. Bilirubin is conjugated with glucuronic acid in the liver to become conjugated bilirubin, which is water-soluble. Conjugated bilirubin passes directly from the liver into the bile duct and then into the intestine where the bacteria reduce it into urobilinogen. Some urobilinogen is then reabsorbed from the intestine into the blood and then is filtered out by the glomerulus in the kidney. This is the reason a small amount of urobilinogen is normally present in urine.

Which of the following answer choices correctly state the use of urine reagent strips for chemical analysis? - Urine chemical reagent strips readers can utilize any manufacturer's dipsticks. - Use of a well-mixed, uncentrifuged urine sample at room temperature is the technique for urine reagent strips. - The urine reagent test strips method is very reliable and quick as the timing for chemical reactions to take place is the same. - The reagent strip can be left in the urine specimen for several minutes without causing any problem.

- Use of a well-mixed, uncentrifuged urine sample at room temperature is the technique for urine reagent strips. Red cells and white cells settle to the bottom of the tube when the urine specimen is not mixed well. This can cause incorrect urine dipstick test results as these cells stay undetected during analysis. Each manufacturer will specify which urine chemical reagent strips are acceptable for use on their instrumentation. The timing for reactions to take place varies between the tests, they are read between 60 and 120 seconds. The reagents are leached from the pads when the strip remains in the urine for an extended time.

The predominant cells seen in this CSF are from a twelve-year-old female exhibiting fever, lethargy, and a stiff neck. The WBC count on the sample was 2,000/microliter. The findings most likely indicate: - Normal cytocentrifuged smear - Viral meningitis - Bacterial meningitis - Alzheimer's disease

- Viral meningitis The cells presented are all mononuclear, and most appear to represent lymphocytes. Given the limited information, the most likely cause of this picture is viral meningitis which is the most common type of meningitis. While the most common type of leukocyte found in a normal centrifuged smear for a person of this age would be lymphocytes, the WBC count, combined with the symptoms does not suggest the sample is normal. A patient with bacterial meningitis would have neutrophils as the significant leukocyte population in the CSF. A patient with Alzheimer's disease is not likely to have any abnormal leukocytes changes in the CSF.

Which of the following casts is characteristically associated with acute pyelonephritis? - Red cell - White cell - Fatty - Waxy

- White cell White cell casts are closely associated with acute pyelonephritis since white blood cells are drawn to the infection and inflammation of the kidney (definition of pyelonephritis) and are encased into casts that slough off into the urine. Red cell casts are indicative of glomerular damage and can be seen in various conditions, but most often nephritic syndromes. Fatty casts are most commonly seen in nephrotic syndromes. Waxy casts are indicative of extreme urine stasis and are most commonly associated with chronic renal failure.