To be diagnosed with
diabetes, you must meet one of the following
criteria:1
- Have symptoms of diabetes (increased thirst,
increased urination, and unexplained weight loss) and a blood sugar level equal
to or greater than 200
milligrams per deciliter (mg/dL). The blood sugar test
is done at any time, without regard for when you last ate (random plasma
glucose test or random blood sugar test).
- Have a fasting blood
sugar level that is equal to or greater than 126 mg/dL. A fasting blood sugar
test (fasting plasma glucose) is done after not eating or drinking anything but
water for 8 hours.
The diagnosis of diabetes needs to be confirmed by repeating the same
blood sugar test or doing a different test on another day.
The American Diabetes Association (ADA) recommends the fasting blood
sugar test for diagnosing diabetes because it is inexpensive, easy to do,
quick, and convenient to use.1 If the results of your
test are between 100 mg/dL and 125 mg/dL, you have
prediabetes, meaning your blood sugar is above normal
but not high enough to be diabetes. Discuss with your health professional how
often you need to be tested.
Some studies have indicated that a hemoglobin A1c or similar test
(glycosylated hemoglobin or glycohemoglobin) may be used to diagnose diabetes;
however, the ADA does not recommend this test for this purpose. The hemoglobin
A1c test estimates the average blood sugar level over the previous 2 to 3
months and is recommended as the test for monitoring blood sugar control after
diagnosis.1
Some health professionals use two blood sugar tests done without
regard to when the person last ate (random blood sugar test) if blood sugar
levels are within the range for diagnosis of diabetes; however, the ADA does
not recommend this method.
Citations
American Diabetes Association (2008). Standards of
medical care in diabetes. Diabetes Care, 31(Suppl 1):
S12-S54.
