July 21, 2000
Diagnosis and Symptoms
Question from Sacramento, California, USA:
I am a 48 year old woman, who is approximately 50 pounds overweight and is exhibiting many symptoms of diabetes. However, my Hemoglobin A1c and glucose tests are in the normal range. I have never had a glucose tolerance test and have been told that it is not performed anymore because it is an outdated test. Do you know if this is accurate information? Is diabetes difficult to diagnose if it is borderline? I am desperate for information as I am rapidly losing my eyesight, all the signs point to diabetes but are unconfirmed by the blood tests.
There are two widely used definitions of significant glucose intolerance. The first is that of the ADA (American Diabetes Association) and requires only an elevated fasting blood sugar. The second is that of the WHO (World Health Organisation) which includes a 2-hour glucose tolerance test value. There have been a number of studies as to whether these two definitions can give the same results and the answer seems to be that the simpler ADA standard is equally good at detecting diabetes. So your doctor is right in saying that GTT’s are rather out of date even though they are still extensively used and also by the ADA definition you do not now have diabetes.
Since you are overweight however it might be important to talk to your doctor about continued occasional testing of blood sugar and also of course to try to lose weight and start more exercise, not an easy task! It seems that your eye problems may have some other basis and only an ophthalmologist can decide that.