Which A1C To Use for the Diagnosis of Diabetes   (May 24, 2013)

Way back in 2009, three diabetes organizations  (the American Diabetes Association (ADA), the International Diabetes Federation (IDF), and the European Association for the Study of Diabetes (EASD)) agreed that the A1C test (AKA “hemoglobin A1C” or "HbA1c" or A1c) was sufficient helpful that it could be used to establish a diagnosis of diabetes, as well as to track the control of people with established diabetes. I wrote about their decision in my essay, Using the A1C test for diagnosing diabetes.

One interesting problem relating to using A1C testing wasn’t definitively answered at that time: which A1C test(s) should be considered accurate enough to use for diagnosing diabetes. The ADA postulated that “The test should be performed in a laboratory using a method that is NGSP [National Glycohemoglobin Standardization Program] certified and standardized to the DCCT assay.” In other words, home A1C tests, and fly-by-night tests that some fly-by-night labs might find cheaper than the certified variety, shouldn’t be used.

But that wasn’t good enough for the FDA. In a press release yesterday, the FDA pointed out that until now, the only A1C tests that they have approved “are FDA-cleared [only] for monitoring a patient’s blood glucose (sugar) control, but not for diagnosing diabetes.” Ahh, that’s now been remedied: one company (Roche) has gone through the regulatory hurdles to have their A1C test approved for the purpose of diagnosis of diabetes. Now the Roche sales reps will be able to boast that they are the only FDA-approved A1C test for diagnosing diabetes.

But I don’t think it’s likely that many physicians (if any!) will demand that Roche’s version of the test be used. I think that the previous ADA advice, to use testing that is NGSP certified and standardized to the DCCT assay” is quite sufficient, and indeed most physicians will trust their laboratory directors to use appropriate testing in any case.

Personally, I think the action by the FDA to evaluate A1C tests differently for diagnosis than for monitoring is splitting hairs, and I really think the FDA has better things to do with its very limited resources than try to one-up the ADA’s prior recommendation.

But I’ll bet the marketing people from Roche feel differently.