Clinical biochemistry: diagnosis of diabetes: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Biochemistry · Clinical biochemistry: diagnosis of diabetes

Sample item

A 45-year-old asymptomatic man has, on the same blood sample, a fasting plasma glucose of 132 mg/dL and an HbA1c of 6.8%. How should this be interpreted?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Diabetes mellitus is confirmed because two different tests are abnormal in the same sample

Diabetes is diagnosed by fasting glucose of 126 mg/dL or more, HbA1c of 6.5% or more, 2-hour OGTT glucose of 200 mg/dL or more, or random glucose of 200 mg/dL or more with symptoms. In the absence of unequivocal hyperglycaemia, two abnormal results are needed, and these may come from different tests in the same sample.

Option by option

  • A. Diabetes mellitus is confirmed because two different tests are abnormal in the same sample (correct)

    Correct. Two concordant abnormal tests confirm the diagnosis.

  • B. Prediabetes, because he has no symptoms

    Both values are above the diabetes thresholds and not within the prediabetes range.

  • C. Not diagnostic; an OGTT is mandatory

    OGTT is not required when two other tests already confirm the diagnosis.

  • D. Not diagnostic; the same tests must be repeated after 3 months

    Waiting 3 months is unnecessary when two tests are abnormal together.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, Diabetes mellitus is confirmed because two different tests are abnormal in the same sample. Diabetes is diagnosed by fasting glucose of 126 mg/dL or more, HbA1c of 6.

Why is "Prediabetes, because he has no symptoms" not the answer?

Both values are above the diabetes thresholds and not within the prediabetes range.

Why is "Not diagnostic; an OGTT is mandatory" not the answer?

OGTT is not required when two other tests already confirm the diagnosis.

Why is "Not diagnostic; the same tests must be repeated after 3 months" not the answer?

Waiting 3 months is unnecessary when two tests are abnormal together.

What concept does this question test?

It tests Clinical biochemistry: diagnosis of diabetes in Biochemistry. 5% or more, 2-hour OGTT glucose of 200 mg/dL or more, or random glucose of 200 mg/dL or more with symptoms. In the absence of unequivocal hyperglycaemia, two abnormal results are needed, and these may come from different tests in the same sample.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Clinical biochemistry: diagnosis of diabetes?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.