What if the 2 Tests are Discordant?
Case Study
Mr. D.R. is 47 years old with longstanding obesity.
Screening tests for type 2 diabetes are done:
-
FPG: 6.3 mmol/L
-
A1C: 6.7%
Should you tell Mr. D.R. that he has type 2 diabetes?
Yes
No
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Reveal Answer
You are correct!
Mr. D.R. has an A1C of 6.7%, which is above the cutpoint for diabetes diagnosis, but a FPG of 6.3 mmol/L, which is in the category of prediabetes (IFG).
To be diagnosed with type 2 diabetes, a confirmatory test must be done on another day.
No, not yet.
Mr. D.R. has an A1C of 6.7%, which is above the cutpoint for diabetes diagnosis, but a FPG of 6.3 mmol/L, which is in the category of prediabetes (IFG).
To be diagnosed with type 2 diabetes, a confirmatory test must be done on another day.
You are correct!
Because of discordance between the A1C (6.7%) and FPG (6.3 mmol/L), the test that is above the diagnostic cutpoint (A1C) should be repeated.
Repeat A1C is 6.6%
Diagnosis of type 2 diabetes is confirmed.
That answer is incorrect.
Because of discordance between the A1C (6.7%) and FPG (6.3 mmol/L), the test that is above the diagnostic cutpoint (A1C) should be repeated.
Repeat A1C is 6.6%
Diagnosis of type 2 diabetes is confirmed.
How to Handle Discordance:
If results of two different tests are available and both are above the diagnostic cut-points, the diagnosis of diabetes is confirmed. When results of more than one test are available (amongst FPG, A1C, 2hPG in a 75-g OGTT) and the results are discordant, the test whose result is above the diagnostic cut-point should be repeated, and the diagnosis is made on the basis of the repeat test.
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