June 29, 2008
Diagnosis and Symptoms
Question from Colorado, USA:
I know diabetes is diagnosed by three different ways: with a fasting number over 125 mg/dl [6.9 mmol/L], a random number of 200 mg/dl [11.1 mmol/L] or higher, or a glucose test of at least 200 mg/dl [11.1 mmol/L] at the two hour mark. I would like to know if type 1 diabetes is ever diagnosed with a glucose test. It seems like people are rarely diagnosed until they have a blood sugar over 300 mg/dl [16.7 mmol/L] and are in the hospital. My son has had continual problems with his blood sugar and I'm getting ready to take him back and have some tests redone. Every time I take my son to the doctor about this, they say his numbers are not normal but aren't out of line enough to consider any type of diabetes even though he is completely symptomatic. For the last year, his blood sugars fluctuated quite a lot. The lowest was 50 mg/dl [2.8 mmol/L] and the highest was over 200 mg/dl [11.1 mmol/L]. He goes to the bathroom a lot, drinks a lot and eats constantly. They did a glucose tolerance test a year ago and his results were as follows: fasting - 75 mg/dl [4.2 mmol/L]; one hour - 50 mg/dl [2.8 mmol/L]; two hours - 70 mg/dl [3.9 mmol/L]; and three hours - 50 mg/dl [2.8 mmol/L]. I asked that the test be redone because, before that, he had never gone low. At home, his fasting fluctuates between 85 mg/dl [4.7 mmol/L] and 110 mg/dl [6.1 mmol/L]. Two hours after a meal, it is usually over 120 mg/dl [6.7 mmol/L].
I suspect you are getting a glucose tolerance test by a non-pediatric endocrinologist since the times of testing are incorrect and there is also no simultaneous insulin level measured. Rarely, such an OGTT needs to be done and usually only for research purposes. When we do such tests, we usually do half hourly tests for four to six hours and almost always then with simultaneous insulin levels. The values you describe could easily be normal variants since you could be missing the 15 to 20 minute peaks and valleys. None of the few blood glucose values you describe are high, however, so this is not likely diabetes. It could be mild hypoglycemia and, if so, almost always responds to meals that avoid simple carbohydrates and focus on complex carbohydrates. The hypoglycemia-like symptoms almost always go away completely with three meals and three snacks high in fats, low in carbohydrates and always spaced about two to three hours apart. If this simple meal plan does not work, then consultation with an experienced pediatric endocrinologist would likely be appropriate. Also, if one is worried about developing future diabetes, then, sometimes, antibody testing is also helpful.