The Four Ways to Diagnose Diabetes

Sripathi R. Kethu, M.D. FACG.

By Sripathi R. Kethu, M.D. FACG.

There are 4 ways to diagnose diabetes. For a long time the most common way to diagnose diabetes was by checking fasting blood glucose level. But there are three other ways that we can diagnose diabetes now. Lets find out.

1. Fasting blood glucose level:

A fasting blood sugar of 126 mg/dL or more, satisfies a diagnosis of type 2 diabetes mellitus. 






2.Oral glucose tolerance test:

This test checks the body’s capacity to lower the blood sugar after taking a concentrated amount of glucose. This also needs fasting for 8 hours prior to the test. After fasting blood sugar is taken, 75 grams of glucose dissolved in water is ingested. Blood is drawn again after the 1st and 2nd hour. If the blood sugar on the 2nd hour is more than or equal to 200mg/dl, diabetes is considered.




3. Random Blood Sugar Level:blank

Random Blood Sugar of at least 200 mg/dl with signs and symptoms of diabetes: This test has the lowest reliability and should be confirmed with another test in diagnosing diabetes.




blank4.Glycosylated Hemoglobin (Hemoglobin A1C or Hgb A1C) Level:

Generally called “A1C test”, this is the newest way to diagnose diabetes. While a few of us learned that we have diabetes after we had an oral glucose tolerance test, that has always been the least common diagnostic tool for diabetes now. The quickest and easiest is clearly the A1C test.

This determines the level of control of blood sugar in the last 2 to 3 months. It checks the level of sugar that has attached to the red blood cell. A level of 6.5% or greater is diagnostic of diabetes.

Because of its advantages, the A1C may now be the most common way we learn that we have this chronic disease.

It’s the only one of these four tests that doesn’t require fasting before hand.


Sripathi R. Kethu, M.D. FACG.

Sripathi R. Kethu, M.D. FACG.

Dr Kethu is a practicing Gastroenterologist. He is a healthcare and real estate entrepreneur. He writes frequently on topics related to health care, healthy living, and physical fitness. He is the author of Amazon’s best-selling book, “The IBS Guide”. He is an avid marathon runner and is on track to finish his 100th marathon in 2024.

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