Physicians use a glucose test to determine if you have diabetes
and if so, how to prevent or slow down diabetes complications.
What Is a Glucose Test? A physician orders a glucose test when
they are trying to diagnose diabetes. There are two main types
of glucose tests: - Fasting Plasma Glucose Test (FPG): In order
for this test to be effective, you must fast from all food or
drink except water for eight hours before the test. A technician
draws your blood into vials. Then at the laboratory, your plasma
— the fluid part of your blood — is used to determine the level
of glucose in your plasma. - Oral Glucose Tolerance Test (OGTT):
This test evaluates how well your body handles a set amount of
glucose. A lab technician draws your first blood sample and then
gives you a premeasured glucose beverage to drink. After two
hours, your blood is drawn again to determine how well your
blood has processed the sugar. Your physician will then compare
the two blood samples. The results of these tests, in addition
to other s