December 29, 2001
Diagnosis and Symptoms
Question from Clearwater, Florida, USA:
I am 25 years old and weigh 98 pounds. About six months ago, I was diagnosed with diabetes and would like some help translating lab results. My blood sugar was 750 mg/dl [41.2 mmol/L], my urine and blood were positive for ketones (but I was not in ketoacidosis). The nurse practitioner said that I have type 1 diabetes, but I did not receive any explanation beyond that. Can you please explain if the results are negative/positive and what they mean? Test Result Normal C-peptide 1.4 ng/ml 0.9-4.0 ng/ml (fasting), 1.5-9.5 ng/ml (stimulated) GAD antibodies 60.9 less than 2.5 islet cell antibodies 18 less than 12 islet cell IgG autoantibodies 80 less than 5 I would also like to know if people with type 2 diabetes can have ketones in the urine and blood.
With an initial blood sugar of 750 mg/dl [41.2 mmol/L] and ketones in the blood and urine, I would be very surprised if you weren’t in DKA [diabetic ketoacidosis] too, but you would have to ask what your blood pH [acid level] or plasma bicarbonate was to be absolutely sure. At all events, the tests that really determine what kind of diabetes you have are the positive anti-GAD test and the two positive islet cell antibody tests.
As the nurse practitioner said, these make it clear that you have type 1A (autoimmune) diabetes, although nowadays in view of your age, this would be more appropriately called Late-onset Autoimmune Diabetes of Adulthood (LADA). People with type 2 diabetes can present with ketoacidosis, but this diagnosis is ruled out by the positive antibody tests and by the low C-peptide level.
The distinction between these two main forms of diabetes is important because on the one hand you will be in some way insulin dependent for life and also because you are likely to benefit from some of the new ideas on the transplantation of insulin producing cells where tolerance can be permanently induced by only a brief period of immunosuppression whilst still in your thirties. This should encourage you to keep in the best possible control until this can take place.