Tests for Diabetes

There are several tests for diabetes that aid in both diagnosing diabetes and in directing and following the management of the disease. In other words, some are tests that help make the initial diagnosis of diabetes and some help to monitor patients with the disease to guide the ongoing treatment and to check on the success of treatment.

Here is a brief overview of some of these medical tests:

Tests for Diabetes

• Serum Glucose: The level of glucose in the blood can be measured both by simple fingerstick glucose monitors as well as by a standard laboratory blood test. While any single blood sugar measurement can be misleading in diagnosing diabetes, it is frequently used to monitor blood sugar levels and to help guide treatment. If used in a fasting patient (after not eating anything for 8-12 hours) the accuracy in diagnosing diabetes improves, particularly if coupled with a glucose tolerance test (see below).
• Hemoglobin A1C: While blood sugar levels fluctuate throughout the day, measurement of hemoglobin A1C gives a rough estimate of the average glucose levels in the blood over time. Therefore, it is a blood test which helps physicians follow patients with diabetes and determine if their treatment is adequate. It is an important test because improvement in hemoglobin A1C is correlated with a decreased risk for most of the complications of chronic diabetes, making it a very good target for treatment success.
• Glucose Tolerance Test: Because any single glucose level can be misleading, a more accurate way to assess diabetes is to test the patient's metabolic response to glucose. The patient is given a glucose drink and the blood sugar levels at various time points after injestion of the glucose is measured. While normal people will lower their blood sugar quickly after injestion of sugar, diabetics glucose levels will stay very high for an extended period of time. This is the most commonly used diagnostic test for diabetes.
• Urinalysis: Urinalysis is a simple and quick test done on a urine sample. It identifies several things in urine which may be associated with various diseases and therefore is used as a diagnostic tool in many situations. Although they are usually not found in the urine, in diabetes, elevated levels of sugar and ketones in the blood can both "spill" into the urine resulting in a positive sugar in urine or ketones in urine. There are other conditions in which both of these findings may be present. Therefore, a urinalysis and the finding of these abnormalities is not diagnostic of diabetes but helps as a screening test and can suggest that further testing, such as a glucose tolerance test, may be indicated.