Question 1
Which one of the following statements about acetaminophen metabolism is false?
Choose the single best answer
A. It is metabolized in the kidney
B. It is largely metabolized in the liver to glucuronide and sulfonate conjugates
C. A small amount is metabolized via cytochrome oxidase to a reactive benzoquinoneimine
intermediate
D. This intermediate becomes toxic to the liver once tissue glutathione becomes depleted
CORRECT ANSWER
A;
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.
Question 2
According to the 2010 ADA guidelines, HbA1C percent can be used as an assay to diagnose
diabetes.
True/False
CORRECT ANSWER
1
@THE STUDY VAULT
,T;
The 2010 ADA Clinical Practice Recommendations added measurement of HbA1C as a
diagnostic assay for diagnosis of diabetes.
Question 3
Which of the following conditions would make a sample unsuitable for lactic acid testing?
Choose the single best answer
A. Movement of hand or arm during specimen collection
B. Received in the lab on ice
C. Centrifuged in a refrigerated centrifuge
D. Specimen centrifuged and plasma separated from cells less than 15 minutes after
collection
CORRECT ANSWER
A;
Movement of the muscles in the hand or arm during specimen collection will falsely increase
lactic acid concentration. A blood sample for lactic acid testing should be placed on ice
immediately after collection, centrifuged within 15 minutes of collection, and plasma
immediately separated from cells following centrifugation. If possible, a refrigerated
centrifuge should be used.
Question 4
You are working in a clinical chemistry laboratory and are analyzing a plasma glucose
sample. The sample is flagged by the analyzer for being "outside of linear range." You
manually dilute the sample 1:2 and rerun it. Again, you receive an "outside linear range"
alert. You decide to perform a different manual dilution. This time you manually dilute the
original sample again; this time using a 1:3 dilution. The instrument gives you a glucose
value of 150 mg/dL from this diluted sample. What is the actual patient glucose result that
you should report to the physician?
2
@THE STUDY VAULT
,Choose the single best answer
A. 100 mg/dL
B. 400 mg/dL
C. 600 mg/dL
D. 450 mg/dL
E. 1200 mg/dL
CORRECT ANSWER
D;
The correct response is option D: 450 mg/dl. A 1:3 dilution entails mixing one part patient
sample with two parts diluent, for a total volume of 3 parts. In laboratory dilutions, the total
volume is considered a dilution factor. The dilution factor in this question is 3. So a diluted
sample with a value of 150 would need to be multiplied by 3 to obtain the correct final
answer. 150 x 3 = 450 mg/dl.
Question 5
That portion of an enzyme which is separated from its cofactor is called a(n):
Choose the single best answer
A. Partial enzyme
B. Isoenzyme
C. Coenzyme
D. Apoenzyme
CORRECT ANSWER
D;
3
@THE STUDY VAULT
, A partial enzyme is not an actual term used in the laboratory. An isoenzyme is a related
enzyme with a different chemical structure. Finally, a coenzyme is a non-protein molecule
(often a vitamin) that helps an enzyme become active.
Question 6
A low CSF glucose level is associated with all the following except:
Choose the single best answer
A. Hyperglycemia
B. Fungal meningitis
C. Toxoplasmosis
D. Hypoglycemia
CORRECT ANSWER
A;
In hyperglycemia you would expect a normal or elevated CSF glucose level- this question is
asking where you would expect to see a decreased (low) CSF glucose level, and in this case
hyperglycemia would be the one condition that is excluded (therefore the correct answer).
Question 7
Blood lactic acid concentration is an indicator of impaired circulation and tissue
oxygenation in critically ill patients. If circulation and tissue oxygenation are impaired,
blood lactic acid concentration will decrease below the lower end of the established
reference range.
True/False
CORRECT ANSWER
False;
4
@THE STUDY VAULT
Which one of the following statements about acetaminophen metabolism is false?
Choose the single best answer
A. It is metabolized in the kidney
B. It is largely metabolized in the liver to glucuronide and sulfonate conjugates
C. A small amount is metabolized via cytochrome oxidase to a reactive benzoquinoneimine
intermediate
D. This intermediate becomes toxic to the liver once tissue glutathione becomes depleted
CORRECT ANSWER
A;
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.
Question 2
According to the 2010 ADA guidelines, HbA1C percent can be used as an assay to diagnose
diabetes.
True/False
CORRECT ANSWER
1
@THE STUDY VAULT
,T;
The 2010 ADA Clinical Practice Recommendations added measurement of HbA1C as a
diagnostic assay for diagnosis of diabetes.
Question 3
Which of the following conditions would make a sample unsuitable for lactic acid testing?
Choose the single best answer
A. Movement of hand or arm during specimen collection
B. Received in the lab on ice
C. Centrifuged in a refrigerated centrifuge
D. Specimen centrifuged and plasma separated from cells less than 15 minutes after
collection
CORRECT ANSWER
A;
Movement of the muscles in the hand or arm during specimen collection will falsely increase
lactic acid concentration. A blood sample for lactic acid testing should be placed on ice
immediately after collection, centrifuged within 15 minutes of collection, and plasma
immediately separated from cells following centrifugation. If possible, a refrigerated
centrifuge should be used.
Question 4
You are working in a clinical chemistry laboratory and are analyzing a plasma glucose
sample. The sample is flagged by the analyzer for being "outside of linear range." You
manually dilute the sample 1:2 and rerun it. Again, you receive an "outside linear range"
alert. You decide to perform a different manual dilution. This time you manually dilute the
original sample again; this time using a 1:3 dilution. The instrument gives you a glucose
value of 150 mg/dL from this diluted sample. What is the actual patient glucose result that
you should report to the physician?
2
@THE STUDY VAULT
,Choose the single best answer
A. 100 mg/dL
B. 400 mg/dL
C. 600 mg/dL
D. 450 mg/dL
E. 1200 mg/dL
CORRECT ANSWER
D;
The correct response is option D: 450 mg/dl. A 1:3 dilution entails mixing one part patient
sample with two parts diluent, for a total volume of 3 parts. In laboratory dilutions, the total
volume is considered a dilution factor. The dilution factor in this question is 3. So a diluted
sample with a value of 150 would need to be multiplied by 3 to obtain the correct final
answer. 150 x 3 = 450 mg/dl.
Question 5
That portion of an enzyme which is separated from its cofactor is called a(n):
Choose the single best answer
A. Partial enzyme
B. Isoenzyme
C. Coenzyme
D. Apoenzyme
CORRECT ANSWER
D;
3
@THE STUDY VAULT
, A partial enzyme is not an actual term used in the laboratory. An isoenzyme is a related
enzyme with a different chemical structure. Finally, a coenzyme is a non-protein molecule
(often a vitamin) that helps an enzyme become active.
Question 6
A low CSF glucose level is associated with all the following except:
Choose the single best answer
A. Hyperglycemia
B. Fungal meningitis
C. Toxoplasmosis
D. Hypoglycemia
CORRECT ANSWER
A;
In hyperglycemia you would expect a normal or elevated CSF glucose level- this question is
asking where you would expect to see a decreased (low) CSF glucose level, and in this case
hyperglycemia would be the one condition that is excluded (therefore the correct answer).
Question 7
Blood lactic acid concentration is an indicator of impaired circulation and tissue
oxygenation in critically ill patients. If circulation and tissue oxygenation are impaired,
blood lactic acid concentration will decrease below the lower end of the established
reference range.
True/False
CORRECT ANSWER
False;
4
@THE STUDY VAULT
