June 20, 2001
Diagnosis and Symptoms
Question from New Orleans, Louisiana, USA:
I am a 22 year old college student who recently has have been feeling unusually tired and did a glucose test using my mom's meter (she developed type�1 diabetes in her twenties after receiving a German measles vaccine). My blood sugar (less than an hour after breakfast) was 204 mg/dl [11.3 mmol/L]. Is this one time test is abnormal enough to be concerned about? What would be "normal"? Should I do some more at home tests before I go to the expense and worry of going to a doctor and getting a glucose tolerance test?
My recommendation is that you have a fasting blood sugar taken at your regularly scheduled visit with your physician. The other acute symptoms of hyperglycemia include weight loss, thirst, frequent urination, and blurring of vision. If you are having these symptoms, contact your physician for a more immediate schedule for testing. The problem with measuring a random glucose is that there are no standard results to compare to in order to tell you if the result is abnormal or not. In addition, the home glucose meter is not recommended for making a diagnosis.
Additional comments from Stephanie Schwartz, diabetes nurse specialist:
It certainly would not hurt to check a few more blood sugars on your mom’s meter, even though (as Dr. Lane has said) they cannot be used to make a diagnosis. If you have symptoms of diabetesor you see more random readings greater than 200 mg/dl [11.1 mmol/L] or fasting readings greater than 126 mg/dl [7 mmol/L], contact your physician as soon as possible.
[Editor’s comment: Testing for diabetes should include blood sugar levels performed by a medical laboratory. The timing of the sample (fasting, random, or postprandial) would influence how high a level is considered abnormal. See Classification and Diagnosis of Diabetes for further information.
Occasionally, lab blood sugar testing might be normal in an early case of diabetes, repeat blood sugar testing at the same or a different time, or performing a glucose tolerance test, might be appropriate if there is a high suspicion of diabetes despite normal initial testing. Another test, the glycosylated hemoglobin, might be used to help confirm a suspected diagnosis of diabetes, but the GHB (also called HbA1c or A1c) is not usually considered as appropriate to make an initial diagnosis. Antibody testing is occasionally done as a screening test in high-risk situations, or as confirmatory of type�1A (autoimmune) diabetes, but is not part of routine testing.
Urine sugar tests or home glucose testing, if done, might be positive, which would make the situation more urgent to get lab testing done to confirm the abnormal results. However, urine or home glucose testing, if negative, would not exclude diabetes.