CLS 251 Chemistry

Hemoglobin A1C(HbA1C)percent can be used as a assay to diagnose which of the following conditions?

Diabetes

Bioavailability of an oral drug refers to the :

Fraction of the drug that is absorbed into systemic circulation Bioavailability (BA or F ) is a subcategory of absorption and is the fraction of an administered dose of unchanged drug that reaches the systemic circulation

Which of the following enzymes is the most sensitive indicator of long term liver damage associated with alcohol ingestion:

GGT elevations precede those of other liver enzymes in cases of chronic ingestion of drugs or alcohol.

Which of the following serum constituents is unstable if a blood specimen is left standing at room temperature for eight hours before centrifugation and processing?

Glucose is utilized by red blood cells even after blood collection. Therefore, the glucose levels will decline over time if left standing for extended periods of time.

Which of the following substances is conjugated with the "indirect" bilirubin to form "direct" bilirubin?

Glucuronic Acid Indirect bilirubin, also known as unconjugated bilirubin, is conjugated with two molecules of glucuronic acid to form direct, or conjugated bilirubin, which is water-soluble. Ascorbic acid, also known as vitamin C, uric acid, or salicylic acid do not conjugate with bilirubin.

Which test is performed to assess the average plasma glucose level that an individual maintained during the previous 10 week to 12 week period?

Glycated hemoglobin, also known as hemoglobin A1C, is hemoglobin that has a glucose group irreversibly attached. The glycated hemoglobin can detect the average levels of glucose over a 2-3 month period of time and is frequently used to monitor the glucose levels of diabetics.

What is the most significant cause of decreased haptoglobin levels?

Haptoglobin is a protein produced by the liver that the body uses to clear free hemoglobin (found outside of red blood cells) from circulation. This test measures the amount of haptoglobin in the blood. (So.. I think this means decrease Haptoglobin = Liver problem. Increase Haptoglobin = Hemolysis)

An adult's plasma cortisol of 22 ug/dL at 8:00 a.m. and 10 ug/dL at 4:00 p.m. would be:

Healthy Cortisol is diurnal

Which of the following parts of the body synthesizes are secretes BNP?

Heart

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 Feedback During a traumatic stick, the red blood cells often become severly hemolyzed, or break apart, during the blood collection process. When this occurs, the potassium will leak out of red blood cells into the plasma causing a falsely elevated potassium result.

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 Increased alpha-fetoprotein levels in adults is usually associated with hepatocelluar carcinoma, as it is a tumor maker in this population. Alcoholic cirrhosis, megaloblastic anemia, and mutliple myeloma would not cause an increase in serum AFP.

Which of the following statements about diagnosing gestational diabetes is true?

I picked: b. All non-diabetic pregnant women should be screened at 24 to 28 weeks of gestation. Not entirely sure though.

Which of the following tests confirms the presence of Bence-Jones proteinuria:

Immunoelectrophoresis

Which of the following methods may be employed to definitively identify Bence-Jones proteins?

Imunnoelectrophoresis

Patients who develop severe sepsis or septic shock commonly have plasma lactate values.

Increased Patients who develop severe sepsis or septic shock commonly have increased plasma lactic acid values.

In healthy individuals, calcitonin is synthesized by which cells in the body?

Thyroid C Cells

Circulating organic iodine is found primarily in the form of:

Thyroxine Iodine circulates as thyroxine (T4) and to and to a lesser extent as Triiodothyronine (T3).

To assess drug concentrations during the trough phase, blood should be drawn:

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: Oral: One hour after drug is taken (assumes a half-life of > two hours) IV: 15-30 minutes after injection/infusion Intramuscular (IM): 30 minutes - one hour after injection

Total iron-binding capacity measures the serum iron transporting capacity of :

Transferrin Transferrin is a glycoprotein that reversibly binds iron. Total iron binding capacity measures the amount of transferrin that is available to bind with iron in the serum.

Elevation is conjugated bilirubin is most likely to be found in which of the following conditions?

Fairly certain it's due to a *Biliary obstruction* because all other diseases listed increase in unconjugated bilirubin.

What additional fraction would be seen if plasma rather than serum was subjected to electrophoresis:

Fibrinogen present in plasma would form a band between the beta and gamma globulins.

All of the following have an impact on electrophoresis techniques in the clinical lab EXCEPT?

Amount of light present in electrophoresis box

Atherosclerosis is due to which of the following?

All of the above (Couldn't find this one.. but..) Plaque = Made up of Lipids + Calcium Platelets = Can get caught on plaque and cause clots. Hypercalcemia = Calcium makes up plaque

Which of the following lipid tests is Lease affected by the fasting status of the patient?

(Good typo) cholesterol

Pheochromocytoma is a tumor of the adrenal medulla that results in elevated urinary levels of all the following EXCEPT:

-All seem elevated -People who have a rare type of tumor called a pheochromocytoma have high levels of catecholamines in their urine. -Vanillylmandelic acid (VMA) and other catecholamine metabolites (homovanillic acid [HVA] and dopamine) are typically elevated in patients with catecholamine-secreting tumors (eg, neuroblastoma, pheochromocytoma, and other neural crest tumors).

A serum sample is received in the clinical chemistry department of the laboratory. The first time the sample is assayed, the result is 600 mg/dL. To verify this result (following this hospital's policy), the tech makes 2 mL of a 1:2 dilution of the original sample. If only 1 mL of this sample is analyzed, what would the result be? Assume that the original 600 mg/dL value was accurate and that the instrument did not automatically perform a dilution calculation.

300 mg/dL

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.

Anion Gap: Na+ - (Cl- + HCO3-) (145) - (113 + 24) = 8 mmol/L

A drug that is administered through which of the following routes will reach peak level the quickest?

A drug that is administered IV will reach peak level the quickest (15 - 30 minutes after injection/infusion). A drug that is injected IM will reach peak level at 30 minutes to one hour after injection; a drug that is taken orally will reach peak level approximately one hour after the drug is taken (if the half-life is > two hours).

What weight of H2SO4 is contained in 200 ML of a 4 molar H2SO4 solution? (Atomic weight: H=1;S=32;0=16)

A; Molarity x Molecular Weight x Volume = Grams Molecular Weight (aka Formula Weight) = 2(1) + 32 + 4(16) = 98 So, 4 x 98 x 0.2L = 78.4g

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 high specificity?

Accurately identifies the absence of disease 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 immunoassay has high specificity, so it has few false-positives and will accurately detect those individuals who do not have the disease or condition that is being tested for. However, the test has low sensitivity, so it may not identify all individuals who actually have the disease; it may produce many false-negative results.

A deficiency in which of these vitamins leads to increased clotting time and may result in hemorrhagic disease?

Adequate amounts of vitamin K are required for the synthesis of prothrombin by the liver. Because prothrombin is an essential component of the clotting system, a deficiency of vitamin K leads to a deficiency of prothrombin, which results in a delayed clot formation = increased clotting time

Which adipokine is decreased in obesity, is anti-inflammatory, and increases insulin sensitivity?

Adiponectin is a protective cytokine. This cytokine is anti-inflammatory and increases insulin sensitivity. Adiponectin is usually decreased in obesity.

Which one of the following usually shows a decrease during an acute phase response?

Albumin is a "negative" acute phase protein since it is found in decreased levels during acute phase response. Alpha-1-antitrypsin, fibrinogen, and ceruloplasmin are all "positive" acute phase proteins that are found in increased levels during acute phase response.

A physician needs to prescribe a drug to a patient but the drug has a narrow therapeutic window. 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. The drug should be measured at a time corresponding to the peak concentration (not the trough). One to 2 hours after an oral dose is usually sufficient time for a drug to be absorbed and should correspond to peak concentration. A drug measurement that is taken 2 to 4 hours after an IV injection of the drug will not represent the peak value. A drug that is given via IV enters the circulation immediately, and the peak concentration of the drug would be measured 15 to 30 minutes after the IV injection. A measurement that is taken just before the next dose is given represents the trough value of the drug.

Which of the following is true of genotype screening in pharmacogenomics?

B Genotyping, while more robust and definitive, cannot factor in environmental or health variables that could affect drug metabolism. Probe drug analysis does factor in these variables, but it is more complex and tedious. Genotyping typically involves measuring many polymorphisms. For example, a laboratory that offers CYP2D6 profiling may measure twelve of the most common and significant mutation sites on this enzyme.

Which assay is performed to diagnose congestive heart failure (CHF)?

BNP is elevated in CHF patients. Cardiac troponins are measured to diagnose an AMI and homoscysteine, hs-CRP, and ischemia modified albumin are markers of risk for cardiac disease.

C-reactive protein (CRP) is often used as a marker of inflammation. However, it has a low______.

Because C-reactive protein is part of the immune system, your levels of it rise whenever you have inflammation in your body. However, the test doesn't show where the inflammation is or what is causing it.

Carbon dioxide is predominately found in blood in the form of:

Bicarbonate

MOST of the carbon dioxide present in the blood is in the form of:

Bicarbonate Most of the carbon dioxide in your blood is found in the form of bicarbonate

Estrogen (ERs) and progesterone (PRs) receptors used as tumor markers are most commonly employed to provide prognostic information about:

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.

Which of the following cardiac biomarkers could detect a recent reinfarction?

CK-MB Following an AMI, elevated CK-MB returns to normal ranges in 48-72 hours. If a patient has a second AMI in this time period, a second rise in concentrations of CK-MB would be seen. This is not true for the cardiac troponins since they remain elevated 7-14 days following an AMI.

8-Hydroxyquinoline and Ortho-Cresolphthalein complexone (CPC) reagent is commonly used in the determination of:

Calcium

Which one of the following serum constituents is increased following strenuous exercise:

Creatinine Reduced renal blood flow causes a small increase in serum creatinine. The other analytes mentioned stay the same or decrease after strenuous exercise.

An increased serum level of which of the following analytes is MOST commonly associated with decreased glomerular filtration?

Creatinine 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.

Which nitrogen base would bind with a guanine nucleotide in forming double-stranded DNA?

Cytosine

Hemoglobin A1C (HbA1C) percent can be used as an assay to diagnose which of the following conditions?

Diabetes The hemoglobin A1c test tells you your average level of blood sugar over the past 2 to 3 months. It's also called HbA1c, glycated hemoglobin test, and glycohemoglobin. People who have diabetes need this test regularly to see if their levels are staying within range. It can tell if you need to adjust your diabetes medicines. The A1c test is also used to diagnose diabetes.

Thin-layer chromatography is particularly useful as a tool in the identification of:

Drugs

Which of the following hormones is mainly responsible for the entry of glucose into the cell for energy production?

Insulin is the hormone that is mainly responsible for the entry of glucose into the cell for energy production Glucagon and epinephrine promote glycogenolysis, conversion of glycogen to glucose, which increases plasma glucose. Cortisol, along with glucagon, increases gluconeogenesis, formation of glucose from noncarbohydrates, which also raises plasma glucose concentration.

Which of the following is necessary for the absorption of Vitamin B12

Intrinsic Factor

Which one of the following statements about acetaminophen metabolism is false?

It is metabolized in the kidney The benzoquinoneimine intermediate produced in the liver as a result of hepatic cytochrome oxidase metabolism of acetaminophen is responsible for hepatic necrosis via acylation of hepatic tissue. The treatment of acetaminophen toxicity includes the use of N-acetylcysteine (Mucomyst), which acts as a glutathione substitute. The risk of hepatotoxicity is predicted with the Rumack-Matthew nomogram, which uses the hours after ingestion and plasma acetaminophen level to predict the probability of hepatotoxicity. Severe hepatotoxicity can be fatal.

Calculate LDL cholesterol concentration if total cholesterol is 280 mg/dL, triglyceride is 100 mg/dL, and the HDL cholesterol is 40.0 mg/dL.

LDL (mg/dl) = total cholesterol - HDL - (triglycerides / 5) LDL = (280) - (40.0) - (100/5) = 220 LDL mg/dl

Which type of lipoprotein transports the MAJORITY of cholesterol to cells for steroid hormone synthesis or cell membrane incorporation?

LDL: The majority of cholesterol is transported by LDL to the various cells in the body, and the rest is transported by HDL through reverse cholesterol transport for excretion purposes, ultimately through bile or bile salts. VLDL transports endogenous products, whereas chylomicrons transport exogenous (dietary) products."

Which of the following statements is true concerning apolipoproteins?

Lipid Metabolism Apolipoproteins are very important in cholesterol metabolism as they act as enzymes and ligands for receptors mediating lipid modification and absorption

Which of the following is used primarily for the treatment of manic-depression:

Lithium = Manic Depression Lithium is commonly used in the treatment of manic depressive patients. Lithium exerts a dual effect on receptors for the neurotransmitter glutamate; acting to keep the amount of glutamate active between cells at a stable, healthy level, neither too much

Which of the following would NOT be considered a normal part of a routine electrolyte panel (profile)?

Magnesium A routine electrolyte panel typically consists of sodium, potassium, chloride, bicarbonate, creatinine, glucose, and BUN.

Serum calcitonin is typically elevated in which of the following conditions?

Medullary carcinoma of the thyroid Serum calcitonin is normally produced by the C cells of the thyroid. If functions to reduce serum calcium by inhibiting release of calcium from bone. It is a peptide with a molecular weight of 3400, and has a half life of approximately 12 minutes. It is characteristically elevated in medullary carcinoma of the thyroid. Since medullary carcinoma often occurs as an autosomal disorder, family members of patients with this condition should be screened for serum calcitonin.

Which analyte measurement is used to detect early nephropathy in a diabetic patient?

Microalbumin The detection of small concentrations of albumin (microalbumin) in the urine is used to detect early renal impairment.

Why are small dense LDL molecules more atherogenic?

Most researchers believe that the small size and increased density of LDL molecules found in atherogenic dyslipidemia enable the molecules to more easily invade the endothelium and arterial wall of vessels.

Creatinine excretion correlates best with which of the following parameters:

Muscle Mass Creatinine is the muscle guy!! Creatinine excretion is related to muscle mass and is fairly constant from day to day for a given individual.

Which two of the following biomarkers are not specific to cardiac muscle and may be elevated in patients with injury to muscle other than cardiac muscle?

Myoglobin and CK-MB are present in skeletal muscle and can be elevated in injury to these cells. Other causes of increased myoglobin and CK-MB levels include: Severe injury to skeletal muscle Strenuous exercise Extremely difficult breathing (increased use of chest muscles) Kidneys failure Chronic muscle disease Alcohol abuse Troponin T and I tests are much more specific to cardiac muscle than myoglobin and CK-MB assays.

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 rises typically within 2-4 hours after a myocardial infarction and stay elevated for days, with a peak at the 6-9-hour mark post-MI. After myoglobin, troponin is the next fastest to rise afer a mycardial infarction and can rise within 3-4 hours with a peak around 12 hours post-MI. LD (8-12 hours, 24-48 hour peak) and CK (4-6 hours with peak at 24-36 hours) will also rise after MI, but are not as fast to rise as myoglobin and troponin.

The measurement of total glycosylated hemoglobin A1C is an effective means of assessing the average blood glucose levels:

Over 2-3 months. The concentration of hemoglobin A1c is directly proportional to the average plasma glucose level that the RBCs are exposed to during their 120 day life span. The glycosylated hemoglobins result from glycosylation of serine, asparagine, and hydroxylysine residues in hemoglobin. There are three glycosylated hemoglobins: Hb A1a, Hb A1b, and Hb A1c, of which Hb A1c constitutes 80%. Most methods measure total gycosylated hemoglobin, which has a high degree of correlation to Hb A1c, and may be reported as such after making the appropriate conversion.

Fetal lung maturity can be determined from amniotic fluid because the surfactant is PRIMARILY composed of:

Phosphatidylcholine and other Phospholipids Assessment of the status of amniotic fluid phospholipids has become important in determining fetal lung maturity. During pregnancy, it has been documented that the ratio of lecithin to sphingomyelin (L/S ratio), with respect to pediatric gestational age, is a reliable predictor of maturity.

Which of the following electrolytes is most likely to be spuriously elevated in a hemolyzed specimen:

Potassium has the highest RBC to serum concentration ratio: approximately 23:1.

The selectivity of an ion-selective electrode is determined by the:

Properties of the membrane used

PH alteration of normal blood in a closed vessel standing at 37 degrees C for 1 hour is approximately:

Says it's .06, so not sure if that's .08 or .04 - I rounded up to .08 The pH of freshly drawn blood decreases at a rate of 0.06 pH units/hour at 37oC, but only 0.006 pH units/hour at 4oC.

Which of the following is most likely to interact with arterial walls, leading to deposition of cholesterol, and initiating or worsening atherosclerosis?

Small dense LDL associated with more than a three-fold increase in the risk of coronary heart disease.

The measurement of 17-ketosteroids (17-KSs) in urine is performed to assess PRIMARILY which organ(s)?

Testes and adrenal cortex. 17-ketosteroids are metabolites of testosterone and adrenal steroid hormones. The majority of testosterone is produced in the testes and the adrenal cortex.

Estriol levels is conjunction with hCG, inhibin A (inhA), and alpha-fetoprotein (AFP) can be obtained during pregnancy to:

The answer is ***NOT***: b. Assess the fetomaternal function

Which of the following enzymes is associated with conditions affecting skeletal muscles?

The answer is ***NOT***: Alkaline phosphatase (This makes now sense to me, but one of the other answers must be better.)

All of the following are characteristics of type 2 diabetes mellitus EXCEPT:

The answer is ***NOT***: Insulin levels may or may NOT be abnormal (I thought this was the answer, but it's not. Here's why I thought why:) I think this is the answer because I found that all the others are correct. In Type 2 Diabetes your insulin is either not working or not being produced. If it's not working, your body will try to make more (Increased Insulin) to compensate for the loss. If it is not being produced you have a decrease in insulin.

An electrophorectic separation of lactate dehydrogenase isoenzyme that demonstrates elevation in LD-1 greater than LD-2 could be indicative of:

The answer is ***NOT***: None of the above. It seems as though the answer is Myocardial Infarction, which isn't listed.

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 he spent a lot of time running between the water fountain and the bathroom. Considering the patient's results and sysptoms, what could be the cause for the osmolality result, and increased thirst? Results: pH=7.11 (7.35-7.45) pCO2= 20mm Hg (35-45 mm Hg) Glucose 1050 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.

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?

Troponin T remains elevated after an AMI for 10-14 days, with an initial elevation within 2-4 hours after onset of myocardial necrosis. Myoglobin returns to normal range within 24-36 hours and CK-MB is back to normal range in 48-72 hours, so neither could be used in this case.

What is the largest constituent of plasma nonprotein nitrogen:

Urea

The results which would be MOST consistent with macro-amylasemia are?

serum elevated, normal urine

Which enzyme is responsible for the conjugation of bilirubin?

glucuronyltransferase

Where are most acute phase proteins synthesized?

liver aka hepatocytes