June 7, 2007
A1c (Glycohemoglobin, HgbA1c), Diagnosis and Symptoms
Question from Gaza, Palestine:
I’m a 38 year old pharmacist with the following history: I am athletic, playing football two or three times a week. I am 6 feet, 10 inches, 230 pounds with a BMI of 30. Although I am healthy, I am a smoker. Forty-five years ago, my father was diagnosed with diabetes. My fasting blood sugars have ranged from 97 mg/dl [5.4 mmol/L] to 112 mg/dl [6.2 mmol/L].
Recent laboratory findings, performed yesterday, are as follows:
Cholesterol 168.3 mg/dl
Triglycerides 95.5 mg/dl
HDL 46 mg/dl
LDL 105.9 mg/dl
FBS 93mg/dl
Glucose Tolerance Test 93 mg/dl [5.2 mmol/L], two hours after drinking 75 cc of glucose
LDL/HDL 2.29
Cholesterol/HDL 3.63
Normal liver and kidney function tests and CBC
The only surprising test result was the A1c, which was confirmed again in another laboratory in the same day. It was 7.9 and 7.5 respectively.
Being a pharmacist with a family history of diabetes, I do perform blood sugar tests approximately every two months. Today was my first time having an A1c test.
For the past three months, I have been taking Xenical, but not regularly.
Why do you think my A1c is this high when my fasting the glucose tolerance test results are normal? Am I considered pre-diabetic or diabetic? What kind of treatment should I have? Is this a common situation? Is it risky?
Answer:
I am concerned you may have a false positive A1c. A false positive test means the test resulted in a positive result, but it is not real. It is an artifact. This may occur if you have a variant hemoglobin. This interferes with the A1c test. This is tested with a hemoglobin electrophoresis. It seems unlikely that you would have such a high hemoglobin A1c in the presence of normal fasting and post-load glucose levels.
JTL
