Tests for Diabetes Management
There are two key blood tests for management of diabetes.
Both give your healthcare provider different information. Both are useful in determining how best to assist you in the management of your diabetes.
The first is the finger stick blood glucose test. This test gives a reading of blood glucose where your blood sugar is right at that particular moment in time.
Since blood sugars are constantly moving up & down based on food intake, exercise, fluid intake, etc., there is another test to give a more meaningful long-term measure. This is the Hemoglobin A1C test.
The A1C test is (in very simplified terms) a measure of your average blood sugar for the past three months. Since red blood cells live only about 3 months, this test will give the average amount of glucose in your blood over that time.
Many times, when you go for lab tests, you may be asked to fast (no eating or drinking anything except water) for the 8 hours before the test. The reason for this is that the blood test will then give your healthcare provider a true picture of the lowest point in your blood sugar.
However, for many people, blood sugar goes up for a few hours after eating long before it remains elevated after fasting for 8 hours. Since the Hemoglobin A1C test looks back over the last 3 months, it doesn’t have that much variation from before meals to after meals. That means that it will give a better indication if the blood sugar spends more time between meals being higher than it should be - even if it all looks “normal” after fasting or sleeping overnight.
Which test is best? It depends on what is needed - immediate control or longer-term review.
Beverly J. Howard, PhD, RN, FNP-BC