Many conditions can change your blood glucose levels. Your doctor will discuss any significant abnormal results with you in relation
to your symptoms and past health.
For more information on results from an oral glucose tolerance test or hemoglobin A1c test, see:
You may have diabetes. To make a diagnosis of type 2 diabetes, your doctor will use the American Diabetes Association's criteria.
Other conditions that can
cause high blood glucose levels include:
A fasting glucose level below 40 mg/dL (2.2 mmol/L) in women or
below 50 mg/dL (2.8 mmol/L) in men that is accompanied by symptoms of
hypoglycemia may mean you have an insulinoma, a tumor
that produces abnormally high amounts of insulin.
levels also may be caused by:
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Eating or drinking less than 8 hours before a
fasting blood test or less than 2 hours before a
2-hour postprandial test.
- Drinking alcohol on the day of the test or several days before the test.
- Illness or
emotional stress, smoking, and caffeine.
- Taking a medicine. Make sure
that your doctor knows about any medicines you take and how often you take
What To Think About
levels in urine can also be measured. Many people with diabetes have glucose in
their urine. But the level in the blood must be very high before glucose can be
detected in the urine. For this reason, tests for glucose in urine are not used
to diagnose or monitor diabetes. To learn more, see Urine Test.
- If you have diabetes, you will
be able to measure your blood glucose levels at home. To learn more, see Home Blood Glucose Test.