Clinical Chemistry Part 2 Flashcards
1
Q
Drugs rapidly infused intravenously usually follow which elimination model?
A. One compartment, first order
B. One compartment, logarithmic
C. Biphasic or two compartment with serum level rapidly falling in the first phase
D. Michaelis–Menton or concentration-dependent elimination
A
C
2
Q
Which fact must be considered when evaluating a patient who displays signs of drug toxicity?
A. Drug metabolites (e.g., N-acetylprocainamide) may need to be measured as well as parent drug
B. If the concentration of total drug is within therapeutic limits, the concentration of free drug cannot be toxic
C. If the drug has a wide therapeutic index, then it will not be toxic
D. A drug level cannot be toxic if the trough is within the published therapeutic range
A
A
3
Q
When a therapeutic drug is suspected of causing toxicity, which specimen is the most appropriate for an initial investigation?
A. Trough blood sample
B. Peak blood sample
C. Urine at the time of symptoms
D. Gastric fluid at the time of symptoms
A
B
4
Q
For which drug group are both peak and trough measurements usually required?
A. Antiarrhythmics
B. Analgesics
C. Tricyclic antidepressants
D. Aminoglycoside antibiotics
A
D
5
Q
Which of the following statements about TLC for drug screening is true?
A. Acidic drugs are extracted in an alkaline nonpolar solvent
B. A drug is identified by comparing its Rf value and staining to standards
C. Testing must be performed using a urine sample
D. Opiates and other alkaloids are extracted at an acid pH
A
B
6
Q
The EMIT for drugs of abuse uses an:
A. Antibody conjugated to a drug
B. Enzyme conjugated to an antibody
C. Enzyme conjugated to a drug
D. Antibody bound to a solid phase
A
C
7
Q
Which statement about EMIT is true?
A. Enzyme activity is inversely proportional to drug level
B. Formation of NADH is monitored at 340 nm
C. ALP is the commonly used conjugate
D. Assay use is restricted to serum
A
B
8
Q
Which statement regarding cloned enzyme donor immunoassay (CEDIA) is true?
A. The enzyme used is glucose-6-phosphate dehydrogenase
B. The enzyme donor and acceptor molecules are fragments of β-galactosidase
C. Drug concentration is inversely related to fluorescence
D. The antibody is covalently linked to the enzyme donor
A
B
9
Q
Whichstatementistrueregardingparticle-enhanced turbidimetric inhibition immunoassay methods for therapeutic drugs?
A. Drug concentration is proportional to light scatter
B. Magnetic separation is needed to remove unbound conjugate
C. When particle-bound drug binds to antibody, light scattering is increased
D. Two antibodies to the drug are needed
A
C
10
Q
Quantitation of a drug by gas chromatography–mass spectroscopy (GC-MS) is usually performed in which mode?
A. Total ion chromatography
B. Selective ion monitoring
C. Ion subtraction
D. Selective reaction monitoring
A
B
11
Q
A urine sample is received in the laboratory with the appropriate custody control form, and a request for drug of abuse screening. Which test result would be cause for rejecting the sample?
A. Temperature after collection 95°F
B. pH 5.0
C. Specific gravity 1.005
D. Creatinine 5 mg/dL
A
D
12
Q
Which substance has the longest detection time?
A. Amphetamines
B. Cocaine
C. Benzodiazepines
D. Marijuana
A
D
13
Q
Which statement about the measurement of carboxyhemoglobin is true?
A. Treatment with alkaline dithionite is used to convert carboxyhemoglobin to oxyhemoglobin
B. Oxyhemoglobin has no absorbance at 540 nm, but carboxyhemoglobin does
C. Bichromatic analysis is required in order to eliminate interference by oxyhemoglobin
D. Carboxyhemoglobin can be measured by potentiometry
A
C
14
Q
Which of the following statements about blood alcohol measurement is correct?
A. Symptoms of intoxication usually begin when the level exceeds 0.05% w/v
B. The skin puncture site should be disinfected with isopropanol
C. The reference method is based upon enzymatic oxidation of ethanol by alcohol dehydrogenase
D. Gas chromatography methods require extraction of ethanol from serum
A
A
15
Q
Which specimen is the sample of choice for lead screening?
A. Whole blood
B. Hair
C. Serum
D. Urine
A
A
16
Q
Which of the following enzymes can be used to measure plasma or serum salicylate?
A. Peroxidase
B. Salicylate esterase
C. Salicylate hydroxylase
D. p-Aminosalicylate oxidase
A
C
17
Q
Which of the following tests is least essential to the operation of an emergency department at a general hospital?
A. Carboxyhemoglobin
B. Osmolality
C. Salicylate
D. Lead
A
D
18
Q
Which of the following trace elements is considered an essential micronutrient?
A. Thallium
B. Aluminum
C. Mercury
D. Selenium
A
D
19
Q
When measuring trace metals in blood other than lead, what type of tube should be used?
A. Navy blue top
B. Green top
C. Purple top
D. Red top
A
A
20
Q
Which whole-blood level is suggestive of excessive exposure to lead in children but not adults?
A. 4 μg/dL
B. 14 μg/dL
C. 28 μg/dL
D. 32 μg/dL
A
B
21
Q
What are the likely laboratory findings in a person suspected of having Wilson’s disease?
A. Blood copper and ceruloplasmin low, urinary copper excretion high
B. Blood and urine copper concentration high, ceruloplasmin low
C. Blood and urine copper concentration high, ceruloplasmin high
D. Blood and urine copper concentration low, ceruloplasmin low
A
A
22
Q
Which of the following tumor markers is classified as a tumor suppressor gene?
A.BRCA-1
B. Carcinoembryonic antigen (CEA)
C. Human chorionic gonadotropin (hCG)
D. Nuclear matrix protein
A
A
23
Q
In general, in which of the following situations is the analysis of a tumor marker most useful?
A. Testing for recurrence
B. Prognosis
C. Screening
D. Diagnosis
A
A
24
Q
Which of the following enzymes is increased in persons with prostate and small-cell lung cancer?
A. Creatine kinase-1 (CK-1)
B. Gamma glutamyl transferase (GGT)
C. Amylase
D. Lactate dehydrogenase
A
A
25
Which of the following is the best analyte to monitor for recurrence of ovarian cancer?
A. CA-15-3
B. CA-19-9
C. CA-125
D. CEA
C
26
Which tumor marker is associated with cancer of the urinary bladder?
A. CA-19-9
B. CA-72-4
C. Nuclear matrix protein
D. Cathepsin-D
C
27
A person presents with a cushingoid appearance and an elevated 24-hour urinary cortisol level. The plasma adrenocotropic hormone (ACTH) is very elevated, and the physician suspects the cause is ectopic ACTH production. Which test would be most useful in substantiating this diagnosis?
A. Plasma cortisol
B. CA-50
C. Alkaline phosphatase isoenzymes
D. AFP
C
28
Which of the following tumor markers is used to monitor persons with breast cancer for recurrence of disease?
A. Cathepsin-D
B. CA-15-3
C. Retinoblastoma gene
D. Estrogen receptor (ER)
B
29
Which of the following statements regarding the Philadelphia chromosome is true?
A. It is seen exclusively in chronic myelogenous leukemia
B. It results from a translocation
C. It appears as a short-arm deletion of chromosome 21
D. It is associated with a poor prognosis
B
30
What is the primary clinical utility of measuring CEA?
A. Diagnosis of liver cancer
B. Diagnosis of colorectal cancer
C. Screening for cancers of endodermal origin
D. Monitoring for recurrence of cancer
D
31
Which tumor marker is used to determine the usefulness of trastuzumab (Herceptin) therapy for breast cancer?
A. PR
B. CEA
C. HER-2/neu
D. Myc
C
32
A person is suspected of having testicular cancer. Which type of hCG test would be most useful?
A. Plasma immunoassay for intact hCG only
B. Plasma immunoassay for intact hCG and the β-hCG subunit
C. Plasma immunoassay for the free alpha and β-hCG subunits
D. Urine assay for hCG β core
B
33
A patient treated for a germ cell tumor has a total and free β-hCG assay performed prior to surgery. The result is 40,000 mIU/mL. One week following surgery, the hCG is 5,000 mIU/mL. Chemotherapy is started, and the hCG is measured 1 week later and found to be
10,000 mIU/mL. What does this indicate?
A. Recurrence of the tumor
B. Falsely increased hCG owing to drug interference with the assay
C. Analytical error with the test reported as 5,000 mIU/mL
D. Transient hCG increase caused by chemotherapy
D
34
35
Which set of results for ER and PR is associated with the highest likelihood of a favorable response to treatment with estrogen-suppression therapy (tamoxifen)?
A. ER positive, PR positive
B. ER positive, PR negative
C. ER negative, PR positive
D. ER negative, PR negative
A
36
Which type of cancer is associated with the highest level of AFP?
A. Hepatoma
B. Ovarian cancer
C. Testicular cancer
D. Breast cancer
A
37
Which of the following assays is recommended as a screening test for colorectal cancer in persons over 50 years old?
A. CEA
B. AFP
C. Occult blood
D. Fecal trypsin
C
38
Which of the following assays is used to determine the risk of developing cancer?
A. Epidermal growth factor receptor (EGF-R)
B. Squamous cell carcinoma antigen (SCC)
C. c-erb B-2 gene expression
D. p53 gene mutation
D
39
A person has an elevated 24-hour urinary homovanillic acid (HVA) and vanillymandelic acid (VMA). Urinary metanephrines, chromogranin A, and neuron-specific enolase are also elevated but 5-hydroxyindoleacetic acid is within the reference range. What is the most likely diagnosis?
A. Carcinoid tumors of the intestine
B. Pheochromocytoma
C. Neuroblastoma
D. Pancreatic cancer
C
40
In which of the following conditions is PSA least likely to be increased?
A. Precancerous lesions of the prostate
B. Postprostate biopsy
C. Benign prostatic hypertrophy
D. Post–digital rectal examination
D
41
Which of the following statements regarding PSA is true?
A. Complexed PSA in plasma is normally less than free PSA
B. Free PSA below 25% is associated with malignant disease
C. A total PSA below 4 ng/mL rules out malignant disease
D. A total PSA above 10 ng/mL is diagnostic of malignant disease
B
42
A 55-year-old male with early stage prostate cancer diagnosed by biopsy had his prostate gland removed (simple prostatectomy). His PSA prior to surgery was 10.0 ng/mL. If the surgery was successful in completely removing the tumor cells, what would the PSA result be 1 month after surgery?
A. Undetectable
B. 1–3 ng/mL
C. Less than 4 ng/mL
D. Less than 10 ng/mL
A
43
Which of the following procedures can be used to detect proportional error in a new method for glucose?
A. Compare the standard deviation of 40 patient samples to the hexokinase method
B. Measure a mixture made from equal parts of normal and high-QC sera
C. Add 5.0 mg of glucose to 1.0 mL of a serum of known concentration and measure
D. Compare the mean of 40 normal samples to the hexokinase method
C
44
Which of two instruments can be assumed to have the narrower bandpass? Assume that wavelength is accurately calibrated.
A. The instrument giving the highest absorbance for a solution of 0.1 mmol/L NADH at 340 nm
B. The instrument giving the lowest %T for a solution of nickel sulfate at 700 nm
C. The instrument giving the highest %T reading for 1.0% v/v HCl at 350 nm
D. The instrument giving the most linear plot of absorbance versus concentration
A
45
A lipemic sample gives a sodium of 130 mmol/L on an analyzer that uses a 1:50 dilution of serum or plasma before introducing it to the ion selective electrodes. The same sample gives a sodium of 142 mmol/L using a direct (undiluted) ion selective electrode. Assuming acceptable quality control, which of the following is the most appropriate course of action?
A. Report a sodium result of 136 mmol/L
B. Ultracentrifuge the sample and repeat by ISE
C. Dilute the sample 1:4 and repeat by ISE
D. Report the undiluted ion selective electrode result
D
46
A 22S QC error occurs for serum calcium by atomic absorption. Fresh standards prepared in 5.0% w/v albumin are found to be linear, but repeating the controls with fresh material does not improve the QC results. Select the most likely cause of this problem.
A. Matrix effect caused by a viscosity difference between the standards and QC sera
B. Chemical interference caused incomplete atomization
C. Incomplete deconjugation of protein-bound calcium
D. Ionization interference caused by excessive heat
B
47
When calibrating a pH meter, unstable readings occur for both pH 7.00 and 4.00 calibrators, although both can be set to within 0.1 pH unit. Select the most appropriate course of action.
A. Measure the pH of the sample and report to the nearest 0.1 pH
B. Replace both calibrators with unopened buffers and recalibrate
C. Examine the reference electrode junction for salt crystals
D. Move the electrodes to another pH meter and calibrate
C
48
A method calls for extracting an acidic drug from urine with an anion exchange column. The pKa of the drug is 6.5. Extraction is enhanced by adjusting the sample pH to:
A. 8.5
B. 6.5
C. 5.5
D. 4.5
A
49
A patient who has a positive urinalysis for glucose and ketones has a glycated Hgb of 4.0%. A fasting glucose performed the previous day was 180 mg/dL. Assuming acceptable QC, you would:
A. Report the glycosylated Hgb
B. Request a new specimen and repeat the glycosylated Hgb
C. Perform a Hgb electrophoresis on the sample
D. Perform a glucose measurement on the sample
B
50
A peak blood level for orally administered theophylline (therapeutic range 8–20 mg/L) measured at 8 a.m. is 5.0 mg/L. The preceding trough level was 4.6 mg/L. What is the most likely explanation of these results?
A. Laboratory error made on peak measurement
B. Specimen for peak level was collected from wrong patient
C. Blood for peak level was drawn too soon
D. Elimination rate has reached maximum
C
51
A stat plasma lithium determined using an ion-selective electrode is measured at
14.0 mmol/L. Select the most appropriate course of action.
A. Immediately report this result
B. Check sample for hemolysis
C. Call for a new specimen
D. Rerun the lithium calibrators
C
52
A chromatogram for blood alcohol (GC) gives broad trailing peaks and increased retention times for ethanol and internal standard. This is most likely caused by:
A. A contaminated injection syringe
B. Water contamination of the column packing
C. Carrier gas flow rate that is too fast
D. Oven temperature that is too high
B
53
A blood sample is left on a phlebotomy tray for 4.5 hours before it is delivered to the laboratory. Which group of tests could be performed?
A. Glucose, Na, K, Cl, TCO2
B. Uric acid, BUN, creatinine
C. Total and direct bilirubin
D. CK, ALT, ALP, AST
B
54
An HPLC assay for procainamide gives an internal standard peak that is 15% greater in area and height for sample 1 than sample 2. The technologist should suspect that:
A. The column pressure increased while sample 2 was being analyzed
B. Less recovery from sample 2 occurred in the extraction step
C. The pH of the mobile phase increased during chromatography of sample 2
D. There was more procainamide in sample 1 than sample 2
B
55
After staining a silica gel plate to determine the L/S ratio, the technologist notes that the lipid standards both migrated 1 cm faster than usual. The technologist should:
A. Repeat the separation on a new silica gel plate
B. Check the pH of the developing solvent
C. Prepare fresh developing solvent and repeat the assay
D. Reduce solvent migration time for all subsequent runs
C
56
A quantitative urine glucose was determined to be 160 mg/dL by the Trinder glucose oxidase method. The sample was refrigerated overnight. The next day, the glucose is repeated and found to be 240 mg/dL using a polarographic method. What is the most likely cause of this discrepancy?
A. Poor precision when performing one of the methods
B. Contamination resulting from overnight storage
C. High levels of reducing substances interfering with the Trinder reaction
D. Positive interference in the polarographic method caused by hematuria
C
57
Serum protein and immunofixation electrophoresis are ordered on a patient. The former is performed, but there is no evidence of a monoclonal protein. Select the best course of action.
A. Perform quantitative Ig G, A, M
B. Perform the IFE on the serum
C. Report the result; request a urine sample for protein electrophoresis
D. Perform IFE on the serum and request a urine sample for IFE
C
58
Hgb electrophoresis is performed and all of the Hgbs have greater anodal mobility than usual. A fast Hgb (Hgb H) is at the edge of the gel and bands are blurred. The voltage is set correctly, but the current reading on the ammeter is too low. Select the course of action that would correct this problem.
A. Reduce the voltage
B. Dilute the buffer and adjust the pH
C. Prepare fresh buffer and repeat the test
D. Reduce the running time
C
59
A technologist is asked to use the serum from a clot tube left over from a chemistry profile run at 8 a.m. for a stat ionized calcium (Cai) at 11 a.m. The technologist should:
A. Perform the assay on the 8 a.m. sample
B. Perform the test only if the serum container was tightly capped
C. Perform the assay on the 8 a.m. sample only if it was refrigerated
D. Request a new sample
D
60
A gastric fluid from a patient suspected of having taken an overdose of amphetamine is sent to the laboratory for analysis. The technologist should:
A. Perform an EMIT assay for amphetamine
B. Refuse the sample and request serum or urine
C. Dilute 1:10 with H2O and filter; perform TLC for amphetamines
D. Titrate to pH 7.0, then follow procedure for measuring amphetamine in urine
C
61
After installing a new analyzer and reviewing
the results of patients for 1 month, the lead technologist notices a greater frequency of patients with abnormally high triglyceride results. Analysis of all chemistry profiles run the next day indicated that triglyceride results are abnormal whenever the test is run immediately after any sample that is measured for lipase. These observations point to which type of error?
A. Specificity of the triglyceride reagents
B. Precision in pipetting of lipemic samples
C. Bias caused by sequence of analysis
D. Reagent carryover
D
62
A digoxin result from a stable patient with a normal electrocardiogram (EKG)
is reported as 7.4 ng/mL (URL 2.6 ng/mL) using an immunofluorescent method. Renal function tests were normal and the patient was not taking any other medications. The assay was repeated and results were the same. The sample was frozen and sent to a reference laboratory for confirmation. The result was 1.6 ng/mL measured by a competitive chemiluminescent procedure. Which best explains the discrepancy in results?
A. The fluorescent immunoassay was performed improperly
B. Digoxin was lower by the chemiluminescent method because it is less sensitive
C. An interfering substance was present that cross-reacted with the antibody in the fluorescent immunoassay
D. Freezing the specimen caused lower results by converting the digoxin to an inactive metabolite
C
63
Analysis of normal and abnormal QCs performed at the beginning of the evening shift revealed a 22s error across levels for triglyceride. Both controls were within the 3s limit. The controls were assayed again, and one control was within the acceptable range and the other was slightly above the 2s limit. No further action was taken and the patient results that were part of the run were reported. Which statement best describes this situation?
A. Appropriate operating procedures were followed
B. Remedial evaluation should have been taken, but otherwise, the actions were appropriate
C. Corrective action should have been taken before the controls were repeated
D. The controls should have been run twice before reporting results
C
64
A biochemical profile routinely performed bimonthly on a renal dialysis patient showed a decreased serum calcium and decreased PTH level. Such a lab result may be explained by which of
the following circumstances?
A. Malignancy
B. Aluminum toxicity
C. Hypervitaminosis D
D. Acidosis
B
65
Two consecutive serum samples give the results shown in the table above (at the top of this page) for a metabolic function profile. The instrument is a random access analyzer
that uses two sample probes. The first probe aspirates a variable amount of serum for the spectrophotometric chemistry tests, and the second probe makes a 1:50 dilution of serum for electrolyte measurements. What is the most likely cause of these results?
A. Both patients have renal failure
B. There is an insufficient amount of sample in both serum tubes
C. There is a fibrin strand in the probe used for the spectrophotometric chemistry tests
D. The same patient’s sample was accidentally run twice
C
66
A patient previously diagnosed with primary hypothyroidism and started on thyroxine replacement therapy is seen for follow-up testing after 2 weeks. The serum-free T4 is normal but the TSH is still elevated. What is the most likely explanation for these results?
A. Laboratory error in measurement of free T4
B. Laboratory error in measurement of TSH
C. In vitro drug interference with the free T4 assay
D. Results are consistent with a euthyroid patient in the early phase of therapy
D
67
A 6-year-old child being treated with phenytoin was recently placed on valproic acid for better control of seizures. After displaying signs of phenytoin toxicity including ataxia,
a stat phenytoin is determined to be 15.0 mg/L (reference range 10–20 mg/L). A peak blood level drawn 5 hours after the last dose is 18.0 mg/L. The valproic acid measured at the same time is within therapeutic limits. Quality control is within acceptable limits for all tests, but the physician questions the accuracy of the results. What is the most appropriate next course of action?
A. Repeat the valproic acid level using the last specimen
B. Repeat the phenytoin on both trough and peak samples using a different method
C. Recommend measurement of free phenytoin using the last specimen
D. Recommend a second trough level be measured
C
68
The results shown in the table above are obtained from three consecutive serum samples using an automated random access analyzer that samples directly from a bar-coded tube. Calibration and QC performed at the start of the shift are within the acceptable range, and no error codes are reported by the analyzer for any tests on the three samples. Upon results verification, what is the most appropriate course of action?
A. Report the results and proceed with other tests since no analytical problems are noted
B. Repeat the controls before continuing with further testing, but report the results
C. Check sample identification prior to reporting
D. Do not report BUN results for these patients or continue BUN testing
D
69
An AFP measured on a 30-year-old pregnant woman at approximately 12 weeks gestation is 2.5 multiples of the median (MOM). What course of action is most appropriate?
A. Repeat the serum AFP in 2 weeks
B. Recommend AFP assay on amniotic fluid
C. Repeat the AFP using the same sample by another method
D. Repeat the AFP using the sample by the same method
A
70
Biochemistry tests are performed 24 hours apart on a patient and delta-check flag is reported for inorganic phosphorus by the laboratory information system. Given the results shown in the table above, identify the most likely cause.
A. Results suggest altered metabolic status caused by poor insulin control
B. The patient was not fasting when the sample was collected on day 2
C. The samples were drawn from two different patients
D. The delta-check limit is invalid when samples are collected 24 or more hours apart
B
71
quantitative sandwich enzyme immunoassay for intact serum hCG was performed on week 4 and the result was 40,000 mIU/mL (reference range 10,000–80,000 mIU/mL). The physician suspected a molar pregnancy and requested that the laboratory repeat the test checking for the hook effect. Which process would identify this problem?
A. Obtain a new plasma specimen and heat inactivate before testing
B. Obtain a urine specimen and perform the assay
C. Perform a qualitative pregnancy test
D. Perform a serial dilution of the sample and repeat the test
D
72
A patient presents to the emergency department with symptoms of intoxication including impaired speech and movement. The plasma osmolality was measured and found to be 330 mOs/kg. The osmolal gap was 40 mOsm/Kg. A blood alcohol was measured by the alcohol dehydrogenase method and found to be 0.15% w/v (150 mg/dL). Electrolyte results showed an increased anion gap. Ethylene glycol intoxication was suspected because the osmolal gap was greater than could be explained by ethanol alone, but gas chromatography was not available. Which of the following would be abnormal if this suspicion proved correct?
A. Arterial blood gases B. Lactic acid
C. Urinary ketones
D. Glucose
A
73
Which of the following is considered a lipid?
a. Chylomicrons
b. LDL
c. Cholesterol
d. HDL
C
74
In the laboratory procedure for the quantification of HDL, the purpose of the dextran sulfate is to:
a. Precipitate all Apo A1 containing lipoproteins
b. Covert cholesterol esters to cholesterol for detection
c. Precipitate all Apo B and Apo A containing lipoproteins
d. Precipitate all Apo B containing proteins
D
75
Which of the following lipoproteins is the smallest of all the lipoproteins and is composed of 50% protein?
a. HDL
b. Chylomicrons
c. LDL
d. Triglycerides
A
76
Which of the following would be most adversely affected by a nonfasting sample?
a. HDL
b. LDL
c. Cholesterol
d. Triglycerides
D
77
Which of the following apoproteins is responsible for receptor binding for IDL and the chylomicron remnant produced in fat transport?
a. Apo A1
b. Apo C
c. Apo E
d. Apo B
C
78
Which of the following enzymes is found bound to HDL and LDL in blood plasma and acts to convert free cholesterol into cholesteryl esters?
a. Cholesterol esterase
b. Cholesterol oxidase
c. Lecithin-cholesterol acyltransferase
d. Lipase
C
79
Which of the following blood samples would serve best to assay lipoproteins because this anticoagulant acts to preserve lipoproteins?
a. EDTA plasma sample
b. Heparin plasma sample
c. Citrate plasma sample
d. Fluoride plasma sample
A
80
Exogenous triglycerides are transported in the plasma in which of the following forms?
a. VLDL
b. Chylomicrons
c. LDL
d. Cholesteryl esters
B
81
A patient presents to his physician for a lipid profile. The following results are received:
HDL=50 mg/dL
Total cholesterol =300 mg/dL
Triglycerides=200 mg/dL
The calculated LDL cholesterol is:
a. 200
b. 210
c. 290
d. 350
B
82
According to the National Cholesterol Education Program, which lipid or lipoprotein class is more important for therapeutic decision making (diet and medication decisions)?
a. Chylomicrons
b. LDL
c. HDL
d. Cholesterol
B
83
Which of the following mechanisms accounts for the elevated plasma level of b-lipoproteins seen in hyperbetalipoproteinemia (Fredrickson’s type II lipoproteinemia)?
a. Elevated insulin found in these patients
b. Apo B-100 receptor defect
c. Apo C-II–activated lipase deficiency
d. LCAT deficiency
B
84
Which enzyme is common to all enzymatic methods for triglyceride measurement?
a. Glycerol phosphate oxidase
b. Glycerol phosphate dehydrogenase
c. Pyruvate kinase
d. Glycerol kinase
D
85
A patient sample is assayed for fasting triglycerides and a triglyceride value of 1036 mg/dL. This value is of immediate concern because of its association with which of the following conditions?
a. Coronary heart disease
b. Diabetes
c. Pancreatitis
d. Gout
C
86
Which of the following apoproteins is inversely related to risk for coronary heart disease and is a surrogate marker for HDL?
a. Apo A-I
b. Apo B
c. Apo B100
d. APO E
A
87
What is the most appropriate fasting procedure when a lipid study of triglycerides, total cholesterol, HDL, and LDL tests are ordered?
a. 8 hours, nothing but water allowed
b. 10hours,water,smoking,coffee,tea(nosugaror
cream) allowed
c. 12 hours, nothing but water allowed
d. 16hours,water,smoking,coffee,tea(nosugaror cream) allowed
C
88
Laboratory tests are performed for a postmeno- pausal, 57-year-old woman as part of an annual physical examination. The patient’s random serum glucose is 220 mg/dL, and the glycated hemoglobin (HbA1c) is 11%. Based on this information, this patient would mostly likely be classified as:
a. Normal
b. Impaired
c. Having type 1 diabetes
d. Having type 2 diabetes
D
89
Which of the biochemical processes below is pro- moted by insulin?
a. Glycogenolysis
b. Gluconeogenesis
c. Esterification of cholesterol
d. Uptake of glucose by the cells
D
90
Laboratory results for a patient with type 2 diabetes are as follows:
Glucose=128 mg/dL
Total cholesterol = 195 mg/dL
HDL= 45 mg/dL
LDL= 105 mg/dL
BUN= 38 mg/dL
Creatinine = 2.1 mg/dL
Microalbuminuria = 54 mg/Ml
AST= 28 U/L
ALT= 38 U/L
Which of the following statements is correct regarding this patient?
a. Patient is at increased risk for cardiovascular disease
b. Patient is at increased risk for diabetic nephropathy
c. Patient is at increased risk for liver failure
d. Patient is at risk for hypoglycemia
B
91
At what serum glucose concentration would glucose begin to appear in the urine?
a. 50 mg/dL
b. 75 mg/dL
c. 100 mg/dL
d. 170 mg/dL
D
92
Which of the following laboratory tests is the best marker to detect patients with diabetes who are at risk for developing diabetic nephropathy?
a. Creatinine
b. BUN
c. Microalbuminuria test
d. Glucose
C
93
A 68-year-old obese woman visits her doctor report- ing increased urination (especially at night), increased thirst, and increased appetite. Her glucose on examination was 210 mg/dL (fasting). Which of the following statements best fits with the given information above?
a. The patient most likely has type 1 diabetes mellitus
b. The patient would show a positive glucose in her urine
c. The patient would have a decreased glycated hemoglobin
d. Additional testing of this patient should include assessment of hypoglycemia
B
94
Sucrose is considered a disaccharide that on hydrolysis yields which of the following sugars?
a. Glucose
b. Galactose and glucose
c. Maltose and glucose
d. Fructose and glucose
D
95
Which of the following hemoglobin A1c results represents an impaired state according to the American Diabetes Association?
a. 4.5%
b. 5.5%
c. 6.0%
d. 6.5%
C
96
A plasma glucose result is 100 mg/dL.The corresponding glucose in whole blood would approximate:
a. 58 mg/dL
b. 87 mg/dL
c. 98 mg/dL
d. 114 mg/dL
B
97
Which of the following methods is virtually specific for glucose and employs G6PD as a second coupling step requiring magnesium?
a. Hexokinase
b. Glucose oxidase
c. Glucose dehydrogenase
d. Pyruvate kinase
A
98
A 62-year-old patient presents to the physician with report of increased thirst and increased urination, particularly at night. The physician requests a series of tests over the next few days. The following data are received:
Random glucose = 186 mg/dL
Fasting glucose = 114 mg/dL
2-Hour OGTT =153 mg/dL
HbA1c= 5.9%
Which of the following conclusions may be made regarding these data?
a. Data represents normal glucose status
b. Data represents an impaired glucose status
c. Data represents the presence of an insulinoma
d. Data represents the diagnosis of diabetes
B
99
Which of the following renal conditions is associated with a recent group A b-hemolytic streptococcus infection?
a. Kidney obstruction
b. Acute renal failure
c. Uremic syndrome
d. Acute glomerulonephritis
D
100
The red complex developed in the Jaffe method to determine creatinine measurements is a result of the complexing of creatinine with which of the following?
a. Alkaline picrate
b. Diacetyl monoxide
c. Sulfuric acid
d. Sodium hydroxide
A
101
The kidney is responsible for acid-base balance through the removal of H ions via four major mechanisms. Which of the following describes one of those mechanisms?
a. Reabsorption of H ions in the proximal convo- luted tubule
b. Reaction of H ions with Na in the descending loop of Henle
c. Reaction of H ions with filtered bicarbonate ions
d. Reaction of H ions with ADH in the collecting ducts
C
102
Given the data below, the calculated creatinine clearance corrected for body surface area approximates __________.
Serum creatinine =1.2 mg/dL
Urine creatinine =120 mg/dL
Urine volume =1.75 L/day
Surface area= 1.80 m2
a. 16 mL/min
b. 115 mL/min
c. 126 mL/min
d. 210 mL/min
B
103
Which formula is most accurate in predicting plasma osmolality?
a. Na+2(Cl)+BUN+Glucose
b. 2(Na)+2 (Cl)+Glucose+BUN
c. 2(Na)+Glucose/18+BUN/2.8
d. 2(BUN)+Glucose/18+Cl/2.8
C
104
Which of the following statements regarding serum urea is true?
a. Levels are independent of diet
b. High BUN levels can result from necrotic liver disease
c. BUN is elevated in prerenal as well as renal failure
d. BUN rises earlier and quicker than creatinine in renal damage
C
105
Osmolality can be defined as a measure of the concentration of a solution based on:
a. The number of particles present
b. The number and size of particles present
c. The density of particles present
d. The isoelectric point of a particle
A
106
An increased osmole gap is most commonly seen in which of the following?
a. Type 2 diabetes
b. Pancreatitis
c. Presence of toxins such as ethanol and ethylene glycol
d. Liver failure
C
107
A patient with type 2 diabetes is in for a routine examination with the physician. A series of labora- tory tests are performed, including calculation of an eGFR. The patient’s calculated eGFR is 64 mL/ min. This result is most indicative of:
a. A normal state
b. Abnormal glucose control
c. Mild kidney damage
d. Kidney failure
C
108
A healthy 28-year-old female sees her physician for a routine examination and receives a “relatively” clean bill of health except for the results below.
Total bilirubin 2.8 mg/dL
Direct bilirubin 0.1 mg/dL
Indirect bilirubin 2.7 mg/dL
These results most likely indicate which of the following?
a. Normal bilirubin metabolism
b. Extrahepatic obstruction
c. Dubin-Johnson syndrome
d. Gilbert’s disease
D
109
Which of the following is measured using glutamate dehydrogenase and is a measure of advanced stages, poor prognosis, and coma in liver disease?
a. Total bilirubin
b. Ammonia
c. Unconjugated bilirubin
d. Urea
B
110
In which of the following disease states would you see an elevation in total bilirubin and conjugated bilirubin only?
a. Biliary obstruction
b. Hemolysis
c. Neonatal jaundice
d. Hepatitis
A
111
In which of the following conditions does no activity of glucuronyl transferase result in increased unconjugated bilirubin and kernicterus in neonates and even- tual death within 18 months?
a. Gilbert’s disease
b. Dubin-Johnson syndrome
c. Crigler-Najjar syndrome
d. Intravascular hemolysis
C
112
In the liver, bilirubin is conjugated in the presence of which of the following?
a. b-Glucuronidase
b. Bilirubin oxidase
c. Uridine diphosphate (UDP)–glucuronyl transferase
d. Peroxidase
C
113
As a reduction product of bilirubin catabolism, this compound is partially reabsorbed from the intestines through the portal circulation for reexcretion by the liver. What is this compound?
a. Urobilinogen
b. Azobilirubin
c. Biliverdin
d. Urobilin
A
114
Hepatocellular damage may be best assessed by which of the following parameters?
a. Serum AST and ALT levels
b. GGT and ALP
c. Bilirubin, GGT, and ALP
d. Ammonia and urea
A
115
Which of the following conditions is caused by deficient secretion of bilirubin into the bile canaliculi?
a. Gilbert’s disease
b. Physiologic jaundice of the newborn
c. Dubin-Johnson syndrome
d. Hemolytic jaundice
C
116
Which of the following enzymes is responsible for the conjugation of bilirubin?
a. Biliverdin reductase
b. Peroxidase
c. UDP–glucuronyl transferase
d. b-Glucuronidase
C
117
Which of the following analytes is the best indicator of hepatobiliary damage?
a. AST
b. ALT
c. ALP
d. Bilirubin
C
118
Which of the following fractions of bilirubin in high concentrations is associated with kernicterus in newborns?
a. Delta bilirubin
b. Unconjugated bilirubin
c. Conjugated bilirubin
d. Unconjugated and delta bilirubin
B
119
The characteristic laboratory finding in alcoholic cirrhosis includes:
a. Moderate elevations in AST and ALT, normal GGT, and normal ALP
b. Slight elevations in AST and ALT, marked eleva tions in ALP, normal GGT
c. Slight elevations in AST, ALT, and GGT and marked elevations in 50 nucleotidase
d. Slight elevations in AST and ALT (AST>ALT), marked elevations in GGT, slight elevations
in ALP
D
120
Which of the following liver conditions shows an increase in both conjugated bilirubin and ALP, man- ifests with antimitochondrial antibodies, and shows a characteristic lipoprotein X on electrophoresis?
a. Hemochromatosis
b. Primary biliary cirrhosis
c. Alcoholic fatty liver
d. Hepatic tumors
B
121
Which set of results is consistent with uncompen- sated metabolic acidosis?
a. pH 7.25, HCO3 15 mmol/L, PCO2 37 mm Hg
b. pH 7.30, HCO3 16 mmol/L, PCO2 28 mm Hg
c. pH 7.45, HCO3 22 mmol/L, PCO2 40 mm Hg
d. pH 7.40, HCO3 25 mmol/L, PCO2 40 mm Hg
A
122
A patient with emphysema who has fluid accu- mulation in the alveolar sacs (causing decreased ventilation) is likely to be in which of the following acid-base clinical states?
a. Respiratory alkalosis
b. Respiratory acidosis
c. Metabolic acidosis
d. Metabolic alkalosis
B
123
Which of the following buffer systems is the most important physiologic buffer system in the body?
a. Hemoglobin
b. Protein
c. Phosphate
d. Bicarbonate/carbonic acid
D
124
To maintain electrical neutrality in the red blood cell, bicarbonate leaves the red blood cell and enters the plasma through an exchange mechanism with which of the following?
a. TCO2
b. Sodium
c. Chloride
d. Phosphate
C
125
Increased PCO2 in a patient most commonly results in which of the following primary acid-base abnormalities?
a. Respiratory acidosis
b. Metabolic acidosis
c. Respiratory alkalosis
d. Metabolic alkalosis
A
126
Which of the following changes will occur with a blood gas sample exposed to room air?
a. pH increased
b. pCOO2 increased
c. pO2 decreased
d. Ionized calcium increased
A
127
Which of the following is the correct collection and handling for the analysis of blood gases?
a. Plastic syringe, dry heparin, store on ice, assay within 1 hour
b. Glass syringe, liquid heparin, store on ice, assay within 15 minutes
c. Glass syringe, no additive, store on ice, assay within 15 minutes
d. Plasticsyringe,dryheparin,storeatroomtemper- ature, assay within 15 minutes
D
128
What is the blood pH when the partial pressure of carbon dioxide (pCO2) is 45 mm Hg and the bicar- bonate is 28 mmol/L?
a. 7.00
b. 7.11
c. 7.33
d. 7.41
D
129
What is the normal ratio of bicarbonate to dissolved carbon dioxide in arterial blood?
a. 1:10
b. 10:1
c. 20:1
d. 1:20
C
130
Which of the following sets of blood gas data is considered normal?
a. pH 7.33, HCO3 18 mmol/L, pCO2 32 mm Hg
b. pH 7.30, HCO3 16 mmol/L, pCO2 28 mm Hg
c. pH 7.45, HCO3 22 mmol/L, pCO2 40 mm Hg
d. pH 7.40, HCO3 25 mmol/L, pCO2 40 mm Hg
D
131
Which of the following values would be seen in uncompensated metabolic acidosis?
a. pH 7.38
b. pCO2 52 mm Hg
c. HCO3 15 mmol/L
d. pH 7.53
C
132
Which of the following blood gas disorders is most commonly associated with an abnormal anion gap?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
A
133
Which of the following statements best describes the predominant feedback system associated with endocrinology?
a. Decreased levels of circulating hormones directly result in the production of hormone from the target organ
b. Increased circulating levels of hormones directly result in the production of releasing factor from the hypothalamus
c. Increased circulating levels of hormones directly result in the production of inhibiting factor from the hypothalamus
d. Normal levels of circulating hormones directly result in the production of hormone from the target organ
C
134
The following laboratory results are from a 54-year- old woman complaining of weight gain, intolerance to heat, fatigue, and not being able to stay awake.
Na=140 mmol/L
K=4.0 mmol/L
Glucose = 75 mg/dL
Aldosterone =8 ng/dL
Ionized Ca =4.8 mg/dL
Mg=2.0 mEq/L
Phos=3.0 mg/dL
TSH=7.2 mU/mL
FT4=1.0 ng/dL
Cortisol= 10ug/dL
Which of the following conditions best fits with the history and data?
a. Hyperthyroidism
b. Cushing’s syndrome
c. Hyperaldosteronism
d. Hypothyroidism
D
135
A 42-year-old woman presents to her physician with truncal obesity, bruising, hypertension, hyperglyce- mia, and increased facial hair. The physician suspects an endocrine disturbance. Significant test results are as follows:
TSH= 3.0 mU/mL
FT4= 1.0 ng/dL
Glucose= 90 mg/dL
Serum cortisol (8 AM)= 45 mg/dL
Plasma ACTH (8 AM)= 152 pg/mL
Urine free cortisol Dexamethasone suppression tests= Increased
Overnight High dose= 300 nmol/L
>50% suppression
What is the most probable condition?
a. Pituitary tumor
b. Addison’s disease
c. Adrenal adenoma
d. Ectopic ACTH production
A
136
Hypothyroidism is best characterized by which of the following sets of test results?
a. TSH 0.2 mU/mL, FT3 8.9 pg/mL, FT4 4.5 ng/dL
b. TSH 8.5 mU/mL, FT3 1.0 pg/mL, FT4 0.5 ng/dL
c. TSH 0.1 mU/mL, FT3 1.1 pg/mL, FT4 0.8 ng/dL
d. TSH 3.9 mU/mL, FT3 3.0 pg/mL, FT4 1.0 ng/dL
B
137
The release of thyroid-releasing hormone (TRH) would result in which of the following actions from the HPT axis?
a. Decreased release of thyroid-stimulating hor- mone from the pituitary gland
b. Increased release of thyroid-stimulating hormone from the thyroid gland
c. Increased release of thyroid hormones from the thyroid glands
d. Increased release of thyroid hormones from the pituitary gland
C
138
A serum thyroid panel reveals an increase in totalT4, normal TSH, and a normal fT4. What is the most likely cause of these results?
a. Increased thyroxine-binding protein
b. Secondary hyperthyroidism
c. Subclinical hypothyroidism
d. Subclinical hyperthyroidism
A
139
Thyroid hormones are derived from which of the following?
a. Histidine
b. Cholesterol
c. Tyrosine
d. Phenylalanine
C
140
In patients with developing subclinical hyperthyroidism, TSH levels will likely be ______, and fT4 will likely be ______.
a. Decreased, increased
b. Increased, decreased
c. Decreased, normal
d. Increased, normal
C
141
A 30-year-old woman is admitted to the hospital. She has truncal obesity, buffalo humpback, moon face, purple striae, hypertension, hyperglycemia, increased facial hair and amenorrhea. The physi- cian orders endocrine testing. The results are as follows:
Urine free cortisol = Increased
Serum cortisol (8 AM) = Increased
Plasma ACTH = Decreased
Dexamethasone suppression test=
Overnight: No suppression
High dose: No suppression
What is the most probable condition?
a. Addison’s disease
b. Cushing’s disease
c. Conn’s syndrome
d. Cushing’s syndrome
D
142
Trophic hormones are produced by the ______, and releasing factors are produced by the ______.
a. Hypothalamus; pituitary
b. Pituitary; hypothalamus
c. Specific endocrine glands; hypothalamus
d. Pituitary; target gland
B
143
When free thyroxine cannot be measured directly, the free thyroxine index (FT4I) may be calculated by using which measured laboratory data?
a. TSH and T3 resin uptake
b. T4 and T3 resin uptake
c. TSH and T4
d. T3 and T3 resin uptake
B
144
The most commonly used challenge test to assist in evaluating a potential growth hormone deficiency is the:
a. Insulin challenge test
b. Dexamethasone suppression test
c. Oral glucose tolerance test
d. Captopril suppression test
A
145
Symptoms of primary adrenal insufficiency (Addison’s disease) include which of the following?
a. Hypercortisolism
b. Hypokalemia
c. Hypertension
d. Acidosis
B
146
A TRH stimulation test is performed, and a flat response is received from this test procedure. This most likely indicates:
a. Secondary hypothyroidism
b. Tertiary hypothyroidism
c. Primary hypothyroidism
d. Secondary hyperthyroidism
A
147
The first step in the synthesis of thyroid hormones is:
a. Iodide trapping
b. Binding of thyroglobulin
c. Oxidation of iodine
d. Oxidation of TG molecule
A
148
Which of the following conditions is a result of cat- echolamine excess, includes two classifications (MEN 1 and MEN 2), and may result in death from severe cardiovascular complications?
a. Cushing’s syndrome
b. Conn’s syndrome
c. Addison’s disease
d. Pheochromocytoma
D
149
The main estrogen produced by the ovaries and used to evaluate ovarian function is:
a. Estriol
b. Estradiol
c. Epiestriol
d. Estrogen
B
150
Which of the following enzymes is the best indicator of pancreatic function?
a. AST
b. ALT
c. GGT
d. Lipase
D
151
Which of the following enzymes catalyzes the con- version of p-nitrophenyl phosphate to a colored p- nitrophenol product?
a. AST
b. ALT
c. ALP
d. GGT
C
152
One international unit of enzyme activity is the amount of enzyme that under specified reaction conditions of substrate concentration, pH, and temperature, causes usage of substrate at the rate of:
a. 1 millimole/min
b. 1 micromole/min
c. 1 nanomole/min
d. 1 picomole/min
B
153
A physician calls to request a CK test on a sample already in the laboratory for coagulation studies. The sample is 1 hour old and has been stored at 4 c. The plasma shows very slight hemolysis. What is the best course of action and the reason for it?
a. Perform the CK assay because no interferent is present
b. Reject the sample because it is slightly hemolyzed
c. Reject the sample because it has been stored too long
d. Reject the sample because the citrate will interfere
D
154
Which of the following statements regarding CK is true?
a. Levels are unaffected by strenuous exercise
b. Levels are unaffected by repeated intramuscular injections
c. Highest levels are seen in Duchenne’s muscular dystrophy
d. The enzyme is highly specific for heart injury
C
155
Which of the following conditions can “physiologically” elevate serum alkaline phosphatase?
a. Hyperparathyroidism
b. Diabetes
c. Third-trimester pregnancy
d. Nephrotic syndrome
C
156
Kinetic enzymatic assays are best performed during which phase of an enzymatic reaction?
a. Linear phase
b. Lag phase
c. Plateau phase
d. Any phase as long as temperature and pH are constant
A
157
A nurse calls the laboratory technologist on duty asking about blood collection for the analysis of enzymes (AST, ALP, ALT, GGT, CK). Which of the following tubes would you suggest the technologist collect?
a. Red top
b. EDTA
c. Oxalate
d. Fluoride
A
158
Which of the following enzymes catalyzes the con- version of starch to glucose and maltose?
a. Lipase
b. Amylase
c. ALT
d. GGT
B
159
Hyperparathyroidism is most consistently associated with which of the following?
a. Hypocalcemia
b. Hypercalciuria
c. Hypophosphatemia
d. Metabolic alkalosis
C
160
What percentage of serum calcium is in the ionized form?
a. 30%
b. 50%
c. 60%
d. 80%
B
161
Which of the following best describes the action of parathyroid hormone?
a. PTH increases calcium and phosphorus reabsorption in the kidney
b. PTH decreases calcium and phosphorus release from bone
c. PTH decreases calcium and increases phosphorus reabsorption in the liver
d. PTH increases calcium reabsorption and decreases phosphorus reabsorption in the kidney
D
162
Which of the following is most likely to produce an elevated plasma potassium result?
a. Hypoparathyroidism
b. Cushing’s syndrome
c. Diarrhea
d. Hemolysis
D
163
Which of the following hormones involved in calcium regulation acts by decreasing both calcium and phosphorous?
a. PTH
b. Calcitonin
c. Vitamin D
d. Cortisol
B
164
Which of the following electrolytes is the chief plasma cation whose main function is maintaining osmotic pressure?
a. Chloride
b. Potassium
c. Sodium
d. Bicarbonate
C
165
Which of the following conditions is associated with hypernatremia?
a. Diabetes insipidus
b. Hypoaldosteronism
c. Diarrhea
d. Acidemia
A
166
Which of the following conditions will elevate ion- ized calcium?
a. Diabetes mellitus
b. Hyperlipidemia
c. Acidosis
d. Alkalosis
C
167
The anion gap is useful (among other things) as an inexpensive measure of quality control for which of the following analytes?
a. Blood gas analyses
b. Sodium, potassium, chloride, and total carbon dioxide
c. Calcium, phosphorus, and magnesium
d. AST, ALT, GGT, and ALP
B
168
Psuedohyperkalemia is most commonly a result of which of the following?
a. Metabolic acidosis
b. Hemolysis
c. Hyperaldosteronism
d. Hyperparathyroidism
B
169
The following results were seen on a blood sample:
Na+ =140 mEq/L
Cl =105 mEq/L
K+= 15.0 mEq/L
HCO3 = 22 mmol/L
The technologist should do which of the following?
a. Report the results
b. Repeat and check the chloride result
c. Repeat and check the Na+ result
d. Check the sample for hemolysis
D
170
The major intracellular cation is which of the following?
a. Potassium
b. Sodium
c. Chloride
d. Bicarbonate
A
171
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