My 40 year old husband had a casual “random sugar test” with a handheld instrument yesterday, and it showed a reading of 166 mg/dl [9.2 mmol/L]. Does he have diabetes? How do I confirm this?

A random blood sugar level done on a hand-held meter is not accurate enough to diagnose diabetes. The level of 166 mg/dl [9.2 mmol/L] may be high, or normal. See Classification and Diagnosis of Diabetes.

I’d ask your husband’s doctor to do a fasting blood sugar in a laboratory along with a urinalysis to confirm or rule out a diagnosis of abnormalities in glucose metabolism.

MS

[Editor’s comment: As Dr. Songini indicates, 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.

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.

WWQ]