August 6, 2002
Diagnosis and Symptoms
Question from Corvallis, Oregon, USA:
I am a 24 year old female with no family history of diabetes, I exercise every morning, am not overweight, and I have none of the symptoms associated with diabetes.However, I had blood tests done, and I was told that I had borderline diabetes. This was supposedly based on an A1c of 6.1%. My blood glucose was completely normal and my urine glucose was negative. Is there any possibility that this test could be related to something else? Could the A1c test be affected by a dramatic change to a healthier diet? My personal doctor did not have many answers and it seemed that he knew little about what the test results actually represent.
Answer:
Please be advised that the diagnosis of diabetes should not be made with the hemoglobin A1c test. Rather, it requires a fasting blood sugar greater than 126 mg/dl [7 mmol/L] on two separate occasions as measured in the clinical laboratory. It is a common misconception that the hemoglobin A1c is sufficient when in reality, it is not sensitive enough an indicator, especially around the values at the upper end of normal. If your values were clearly more than 1% above normal, I would be more likely to believe you have diabetes but would still confirm with fasting glucose levels.
JTL
[Editor’s comment: See Classification and Diagnosis of Diabetes Guidelines.
SS]
