MLT ASCP Chemistry Practice Questions with accurate detailed answers

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MLT ASCP Chemistry Practice Questions with accurate
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detailed answers ||




Which one of the following statements about acetaminophen metabolism is false?
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Choose the single best answer || || || ||




A. It is metabolized in the kidney
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B. It is largely metabolized in the liver to glucuronide and sulfonate conjugates
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C. A small amount is metabolized via cytochrome oxidase to a reactive benzoquinoneimine
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intermediate

D. This intermediate becomes toxic to the liver once tissue glutathione becomes depleted -
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✔✔A; ||




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




According to the 2010 ADA guidelines, HbA1C percent can be used as an assay to diagnose
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diabetes.



True/False - ✔✔T; || ||




The 2010 ADA Clinical Practice Recommendations added measurement of HbA1C as a
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diagnostic assay for diagnosis of diabetes. || || || || ||

,2


Which of the following conditions would make a sample unsuitable for lactic acid testing?
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Choose the single best answer || || || ||




A. Movement of hand or arm during specimen collection
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B. Received in the lab on ice
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C. Centrifuged in a refrigerated centrifuge
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D. Specimen centrifuged and plasma separated from cells less than 15 minutes after
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collection - ✔✔A; || ||




Movement of the muscles in the hand or arm during specimen collection will falsely
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increase lactic acid concentration. A blood sample for lactic acid testing should be placed on
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ice immediately after collection, centrifuged within 15 minutes of collection, and plasma
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immediately separated from cells following centrifugation. If possible, a refrigerated || || || || || || || || || ||




centrifuge should be used. || || ||




You are working in a clinical chemistry laboratory and are analyzing a plasma glucose
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sample. The sample is flagged by the analyzer for being "outside of linear range." You
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manually dilute the sample 1:2 and rerun it. Again, you receive an "outside linear range"
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alert. You decide to perform a different manual dilution. This time you manually dilute the
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original sample again; this time using a 1:3 dilution. The instrument gives you a glucose
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value of 150 mg/dL from this diluted sample. What is the actual patient glucose result that
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you should report to the physician?
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Choose the single best answer || || || ||




A. 100 mg/dL
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B. 400 mg/dL
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C. 600 mg/dL
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D. 450 mg/dL
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E. 1200 mg/dL - ✔✔D;
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, 2


The correct response is option D: 450 mg/dl. A 1:3 dilution entails mixing one part patient
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sample with two parts diluent, for a total volume of 3 parts. In laboratory dilutions, the total
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volume is considered a dilution factor. The dilution factor in this question is 3. So a diluted
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sample with a value of 150 would need to be multiplied by 3 to obtain the correct final
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answer. 150 x 3 = 450 mg/dl. || || || || || ||




That portion of an enzyme which is separated from its cofactor is called a(n):
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Choose the single best answer || || || ||




A. Partial enzyme
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B. Isoenzyme
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C. Coenzyme
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D. Apoenzyme - ✔✔D;
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A partial enzyme is not an actual term used in the laboratory. An isoenzyme is a related
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enzyme with a different chemical structure. Finally, a coenzyme is a non-protein molecule
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(often a vitamin) that helps an enzyme become active.
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A low CSF glucose level is associated with all the following except:
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Choose the single best answer || || || ||




A. Hyperglycemia
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B. Fungal meningitis
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C. Toxoplasmosis
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D. Hypoglycemia - ✔✔A;
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