Your provider may do a random blood glucose test to check the accuracy of your self-monitoring and/or your home meter. She may also test your glucose levels if she is adjusting your medication or treatment routine. Results are provided in plasma glucose values.

The Fructosamine Test

This is another test that measures your blood sugar over a period of time (two to three weeks, as opposed to the eight to twelve weeks measured by the A1C test). The fructosamine test is a measurement of glycated serum proteins, and may be used as a companion to A1C when you want to find out how blood glucose control has responded to treatment changes in a shorter time period. However, it should not be thought of as a replacement for daily glucose monitoring or A1C tests.

Urine Glucose Tests

Available as reagent “dipstick” tests, urinary glucose tests were once the standard method of measuring glucose levels at home for people with diabetes. With the advent of accurate home monitoring systems, urine glucose tests are now usually relegated to the purpose of infrequent screening.

These tests have several drawbacks. First, they are time-delayed — they can't tell you what your blood glucose level is right now, but only several hours later after glucose has filtered into the urine and urine has collected in the bladder and is ready to leave the body. They are also not highly sensitive or specific; a negative urine test can ensure only that your blood glucose levels are below 180 mg/dl (10.0 mmol/l), well above a “controlled” range for most people. And unlike a blood glucose monitor, they cannot detect blood glucose lows at all.

Blood testing is the gold standard for SMBG (self-monitoring of blood glucose levels). However, urine glucose test strips are sometimes used by patients who cannot afford blood-monitoring supplies. They may also be used by patients who can't or won't blood-test due to discomfort or other reasons. If you're having financial difficulties, talk to your health care provider about patient assistance programs that can provide blood glucose testing supplies free of charge.

What About Insulin Tests?

There are several ways of testing glucose levels, but what about insulin testing? There is a way to test insulin — the insulin serum test, which measures the amount of insulin in the bloodstream. However, given its expense and lack of clinical usefulness, it is rarely used in diabetes diagnosis and assessment.

Insulin has a short half-life and is significantly cleared from the body before it even reaches the general circulation. In addition, the test does not differentiate between injected and endogenous (or self-produced) insulin. Instead of testing insulin, assessing levels of c-peptide, a more accurate predictor of beta cell function, is more common.