June 19, 2006
Diagnosis and Symptoms
Question from Stockport, United Kingdom:
As part of a medical test for my job, I recently had a blood test. As I had not had breakfast (or anything to drink) that day, it was, in effect, a fasting test. The fasting blood sugar level was 7.5 mmol/L [135 mg/dl]. The company doctor advised me to see my own physician given the high level, which I did. My doctor repeated the fasting level and found it to be “okay,” i.e., within normal levels (I don’t know what this was).
I have read many previous questions on your web site and know that in similar circumstances you have recommended a Glucose Tolerance Test (GTT). I suggested this to my doctor who said that the general diagnosis for diabetes was two elevated fasting blood levels or one elevated fasting level along with other symptoms. As I didn’t have any excess thirst, urinating, etc., he said that the second normal level was conclusive in it not being diabetes and he would “not prescribe any unnecessary medical tests based on a patients own Internet diagnosis.” I just wondered whether you agreed with this and also, importantly, what could have caused such a high level (with no symptoms)? Is it normal to have a one-time high blood sugar? Why would this happen?
Answer:
Informed patients are good patients. I think you have a valid question. However, there are several ways to get at the answer. The elevated level obtained originally is enough to concern you and make you look at your own health and lifestyle to make sure it is in line. Second, regarding the test result obtained with your own physician, I would insist on knowing what the value was. If it were close, I would insist on a third fasting test or an Oral GTT. I’m afraid the definition of close is subjective, as there are no criteria for such a designation. However, it is known that there can be some variability in fasting glucose results such that a value just inside the normal level may be repeated and found to be elevated.
JTL
