Tests for Diabetes: Learn What Tests are Used to Diagnose Diabetes

Oral Glucose Tolerance Test

Because of the large number of people with diabetes, getting tested for it is becoming more and more commonplace. According to statistics published by the National Diabetes Information Clearinghouse (NDIC), in 2007 there were approximately 23.6 million people, or 7.8 percent of the population that had diabetes, both diagnosed and undiagnosed.

There are two main types of diabetes, categorized as type one and type two. Type one is insulin-dependant and is also known as diabetes mellitus (IDDM) and juvenile-onset diabetes. Type two is generally referred to as adult-onset diabetes and is non-insulin dependant diabetes mellitus (NIDDM). According to NDIC, 90 to 95 perent of all diagnosed diabetes cases are this type.

There are multiple tests for diabetes, and this article will briefly explain some of them.

Fasting Plasma Glucose Test (FPG)

This test is taken after fasting at least 8 hours. The test involves some blood being drawn for analysis. This is the preferred method of testing due to its convenience and low cost. This method of testing is not used with pregnant women.

Oral Glucose Tolerance Test

This test is used with pregnant women to determine if they have gestational diabetes. Special instructions for eating, exercise and medication may be need to be followed in the time prior to the testing – up to three days prior. This test may take up to 4 hours and requires the patient to sit quietly for the duration of the test because activity can interfere with accurate results.

The test requires the patient to drink a glucose drink and then give a blood sample one hour later.

Glucose Tolerance Diagnostic Test

This is a more complete version of the Oral Glucose Tolerance Test. For this test, the patient is required to fast beforehand and to give a baseline blood sample upon arrival at the testing facility. Then a glucose drink will be administered. Additional blood draw will occur at one hour, two hours, and three hours after drink consumption. Sometimes the draws may occur as soon as 30 minutes after consumption or as long as more than 3 hours after consumption.


National Diabetes Statistics, 2007. National Diabetes Information Clearinghouse (NDIC). https://diabetes.niddk.nih.gov/dm/pubs/statistics/index.htm#allages

Diabetes Testing. WebMD. Rewiewed by John A. Seibel, MD on September 11, 2008. https://diabetes.webmd.com/guide/diagnosing-type-2-diabetes

Blood Glucose. Caroline Rhea, RN, BS, MS. [from Healthwise]. July 25, 2007. RevolutionHealth. https://www.revolutionhealth.com/conditions/diabetes/diabetes-basics/blood-glucose-tests/overview

Image Credit

Oral Glucose Tolerance Test. Aydintay. Wikimedia Commons. Public Domain.