Chemistry CLS
Which risk marker has both positive and negative cardiovascular risk integrated into its measurement?
Apo B-100/Apo A-1
A physician needs to prescribe a drug to a patient, but the drug has a narrow therapeutic window. In addition, he is concerned about possible toxic effects. To assess the upper concentration of such a drug, which time for drawing the specimen do you think makes the most sense?
Approximately one hour after an oral dose
Which dye-binding method uses an increase of absorbance at 595 nm to determine the total protein concentration of the specimen?
Coomassie brilliant blue 250
Which of the following analytes would be increased due to delay in centrifugation?
Creatinine
Which of the following additives should be used for the collection of a sample for blood gas analysis?
Heparin
Increased concentrations of alpha-fetoprotein (AFP) in adults are MOST characteristically associated with:
Hepatocellular carcinoma
If CSF tubes numbered #1, #2 and #3 CANNOT be analyzed within one hour, the correct procedure for the microbiology sample tube is to:
Leave it at room temperature
With the development of fetal lung maturity, which of the following phospholipid concentrations in amniotic fluid increases?
Lecithin
In a normal CSF the protein concentration as compared to that in the plasma is generally:
Less than 1%
Methotrexate is a highly toxic medication that blocks DNA synthesis in all cells. What medication needs to be administered after methotrexate to prevent cytotoxic effects in normal cells of the body?
Leucovorin
Which of the following drugs is used primarily for the treatment of manic-depression?
Lithium
Which of the following would most likely occur as the result of hemodilution?
Low serum electrolyte values
Which type of lipoprotein transports the MAJORITY of cholesterol to cells for steroid hormone synthesis or cell membrane incorporation?
Low-density lipoproteins (LDL)
Myoglobin concentration testing is routinely used for all of the following conditions, EXCEPT?
Pulmonary edema
Which of the following terms could be used to describe an analyzer that can test specimens out of sequence?
Random access
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?
Reject the specimen, the potassium test results will be increased
Which of the following hormones is mainly responsible for the entry of glucose into the cell for energy production?
Insulin
Glucose is considered an aldose because:
It contains a terminal carbonyl group, called an aldehyde group.
Which cardiac biomarker is a regulator of myocyte contraction?
cTnT
All of the following analytes would be significantly increased in a plasma sample due to hemolysis, EXCEPT?
sodium
What function in the body does GGT have?
transfer of gamma-glutamyl peptides amino acids, water, and other peptides
Which one of the following statements concerning Vitamin D is correct?
vitamin D acts as a hormone in calcium regulation.
After experiencing extreme jaundice, abdominal pain, and vomiting from extensive hepatocellular damage, a patient's hepatic function panel is analyzed in the laboratory. The result of the ALT is too high for the instrument to read. Since the instrument does not perform automatic dilutions for ALT, the laboratorian performs a dilution using 100 microliters of patient sample to 400 microliters of diluent. The result now reads 369 U/L. How should the laboratorian report this patient's ALT result?
1,845 U/L
Given the following information, calculate the results in mg/24 hrs for a 24-hour urine protein. Total volume for 24 hours = 2,400 mL Urine protein = 2.7 mg/dL
2.7 mg/dL X 2400 mL/24 hr X 1 dL/100 mL = 2.7 mg X 2400 100 = 64.8 mg/24 hr
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 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
How many distinct bands are separated during a standard serum protein electrophoresis?
5
Using the formula for creatinine clearance, calculate the clearance based on the values given below: Urine creatinine: 100 mg/dLPlasma creatinine: 1.9 mg/dL Urine volume: 1375 mL/24hrs Surface Area: 1.2 m2 Round to 1 decimal place.
72 mL/min/m2
In heme synthesis, how many molecules of delta-aminolevulinic acid (ALA) are needed to form one molecule of heme?
8
What blood alcohol concentration has been established as the statutory limit for the operation of a motor vehicle in the United States?
80 mg/dL
The De Ritis ratio is the calculation of AST/ALT and is used for evaluating liver disease. What should the ratio be when ethanol-related liver disease is expected? Please select the single best answer
>2.0
What type of chemical is lithium?
A cationic metal
Which of the following statements regarding the L/S ratio is TRUE?
A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent respiratory distress syndrome (RDS)
Which of the following statements is true regarding cardiovascular disease and adipose tissue? Please select the single best answer
A state of abnormal lipids and lipid levels found in metabolic syndrome contribute to the development of cardiovascular disease
Which of the following is an example of a specimen which requires a chain-of-custody procedure to be followed?
A urine drug screen for pre-employment
A 17-year old African-American male had the following laboratory results: Sickle cell screen = positiveHemoglobin Electrophoresis :Hb S = 40% Hb A = 58% HbA2 = 2% Which of the following is the PROBABLE hemoglobin genotype?
AS
Which of the following analytes would be increased due to delay in centrifugation?
AST
A hepatic function panel A consists of which of the following tests?
AST, ALT, Alkaline Phosphatase, Total Protein, Albumin, Total Bilirubin, Direct Bilirubin
Whole blood glucose values are ____________ plasma glucose values.
About 11% lower
Which of the following would be considered a normal cerebrospinal fluid glucose level if the serum glucose is 70 mg/dL?
About 45 mg/dL
ß-hydroxybutyric acid is formed as the result of an accumulation of which of the following?
Acetyl-CoA
All of the following are considered cutaneous porphyrias, EXCEPT?
Acute intermittent porphyria
Which one of the following usually shows a decrease during an acute phase response?
Albumin
A Comprehensive Metabolic Panel (CMP) consists of which group of tests?
Albumin, Glucose, BUN, Creatinine, Sodium, Potassium, Chloride, CO2, AST, ALT, Alkaline Phosphatase, Total Protein, Total Bilirubin, Calcium
Which of the following blood tests is used to evaluate liver function?
Alkaline phosphatase (ALP)
Which of the following statements about diagnosing gestational diabetes is true?
All non-diabetic pregnant women should be screened at 24 to 28 weeks of gestation.
All of the following have an impact on electrophoresis techniques in the clinical laboratory EXCEPT?
Amount of light present in electrophoresis box
The production of neutral 17-ketosteroids is a measure of which of the following?
Androgen production
The immunoassay procedure for serum hCG utilizes antisera against which subunit of hCG?
Beta
Carbon dioxide is predominately found in the blood in the form of:
Bicarbonate ions
Elevation in conjugated bilirubin is most likely to be found in which of the following conditions?
Biliary obstruction
Which of the following is NOT required for a diagnosis of hereditary hemochromatosis (HH)? Please select the single best answer
Biopsy of liver and/or bone marrow
Which of the following laboratory tests is used as an indicator of inflammation?
C-Reactive Protein (CRP)
The tumor marker associated with ovarian cancer is:
CA-125
Which tumor marker is used for colorectal cancer?
CEA
A CSF glucose value is 62 mg/dL. What would you estimate the serum glucose?
CSF glucose is roughly estimated to be about 2/3 of the serum glucose level in mg/dL. Therefore: 62 mg/dL = 2/3 x serum glucose serum glucose = 62 mg/dL x 3/2 serum glucose = 93 mg/dL
The buffering capacity of blood is maintained by a reversible exchange process between bicarbonate and:
Chloride
A lipid panel consists of which of the following tests?
Cholesterol, Lipoprotein, HDL, Triglycerides
A 64-year old man lost 15 pounds, became weaker, and his face became fuller with a ruddy complexion. His laboratory tests revealed: Serum cortisol8 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:
Cushing's Syndrome
When evaluating a patient for a suspected Wilson's Disease diagnosis, decreased concentrations of ceruloplasmin would be expected along with:
Decreased serum copper
What are the expected results of the laboratory markers in iron deficiency anemia?
Decreased serum iron, increased transferrin, decreased ferritin, decreased percent saturation, and increased total iron-binding capacity.
The most common methods for measuring bilirubin are based on the reaction of bilirubin with:
Diazo reagent
Which condition is caused by deficient secretion of bilirubin into the bile canaliculi?
Dubin-Johnson syndrome
Which values would be expected with metabolic alkalosis?
Elevated pH, increased bicarbonate, normal PCO2
Ninety-nine percent of lead absorbed in the body is taken up by what after absorption?
Erythrocytes
Which of the following is a cause of metabolic alkalosis?
Excessive vomiting
What additional fraction would be seen if plasma rather than serum was subjected to electrophoresis:
Fibrinogen
An adult's plasma cortisol of 22 µg/dL at 8:00 a.m. and 10 µg/dL at 4:00 p.m. would be:
Found in a healthy individual
A normal hemoglobin molecule is comprised of the following:
Four heme and four globin chains
Which of the following is a liver enzyme that is instrumental in allowing glucose to enter the bloodstream?
Glucose-6-phosphatase
Which enzyme is responsible for the conjugation of bilirubin?
Glucuronyl transferase
Acute-phase proteins generally fall into which category?
Glycoproteins
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?
Has many false-negative results
The most likely cause of an elevated serum potassium level in an apparently normal individual is:
Hemolysis
A specimen for potassium was drawn in a tube without anticoagulant at 6 AM during a traumatic patient stick. The results were 6.0 mmol/L. Why are the results elevated?
Hemolysis of the RBC's
An increase is total bilirubin with a normal conjugated bilirubin is most likely indicative of:
Hemolytic disease
Which of the following is the most common technique that is used by clinical laboratories for therapeutic drug monitoring?
Immunoassay
Patients who develop severe sepsis or septic shock commonly have __________ plasma lactate values.
Increased
Which of the following conditions is most likely when an oligoclonal band is seen in CSF electrophoresis without a corresponding serum peak?
Multiple sclerosis
A patient is admitted to the hospital with acute chest pain, but which of the following cardiac markers will be elevated FIRST if the patient had a myocardial infarction (MI)?
Myoglobin
Which of the following cardiac biomarkers rises within 1 - 3 hours after chest pain, peaks in 2 - 6 hours, and is usually normal within 24 hours.
Myoglobin
Enzyme-multiplied immunoassay techniques (EMIT) differ from all other types of enzyme immunoassays in that:
No separation of bound and free antigen is required.
The study of how variations in the human genome affect a given individual's response to medications is called?
Pharmacogenomics (Pharmacogenetics)
Which of the following drugs is listed as an anti-convulsants?
Phenobarbital
Which of the following analytes will be falsely increased due to hemolysis?
Potassium, Magnesium, Iron, Total Protein
Which of the following is the prodrug of phenobarbital?
Primidone
Which of the following contributes to specific gravity but does NOT contribute to osmolality?
Protein
Which one of the following is not an acute phase protein?
Protein S
What are apolipoproteins
Proteins that are on the surface of lipoprotein molecules and bind enzymes or transport specific proteins and direct lipoproteins to their sites of metabolism.
Which of the following describes gastrin's role in digestion
Stimulates gastric acid-HCl secretion
Deviations from Beer's Law are caused by:
Stray light
All of the following are quantitative methods for the determination of albumin EXCEPT?
Sulfosalicyclic acid precipitation
A 14-year-old male was taken to the emergency room in a coma by his school nurse. He had lost 15 pounds in 3 months. His teacher said he was always thirsty and that was he spent a lot of time running between the water fountain and the bathroom. Considering the patient's results and symptoms, what could be the cause for the osmolality result and increased thirst? Results: pH = 7.11 (7.35-7.45) pCO2 = 20 mm Hg (35-45 mm Hg) Glucose 1,050 mg/dL (60-110 mg/dL) Serum osmolality 385 mOsm/Kg (275-295 mOsm/Kg) Urine ketone strongly positive (negative) Urine glucose strongly positive (negative)
The increased glucose level causes a more concentrated extracellular solution, stimulating the thirst center of the hypothalamus.
If a disease or disorder causes serum binding proteins (such as albumin) to decrease, what may occur if the dose of a highly protein-bound drug with a narrow therapeutic window is not adjusted?
The patient may experience toxic effects (high free drug fraction).
The following BEST describes serum hCG levels during pregnancy:
The rapid rise in levels during the first trimester; slow decline and possible level-off throughout the remainder of the pregnancy
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?
The specimen should be centrifuged as soon as it clotted and serum should be transferred to another tube.
Serum TSH levels five times the upper limit of normal in the presence of a low T4 and low T3 uptake could mean which of the following?
The thyroid has been established as the cause of hypothyroidism.
Which of the following drugs is used to treat asthma and COPD in patients with nocturnal symptoms or problems with inhalers?
Theophylline
The following results were obtained on an SPE scan. What can you infer about the specimen from these results?
There is an interfering substance present in the specimen such as hemoglobin due to hemolysis
How is the majority of urobilinogen that is produced daily removed from the body?
Through fecal excretion
A deficiency in which of the following vitamins is associated with "scurvy"?
Vitamin C
