What is an Oral Glucose Tolerance Test?

Oral Glucose tolerance test (OGTT) is a laboratory method to diagnose diabetes in people. Biochemical analysis of blood is strictly recommended by the physicians to attain maximum health. Regular biochemical analysis can prevent people from lots of diseases. These are also helpful to diagnose, treat and control health problems.

Diabetes is one of the most prevalent diseases all over the world and its diagnosis needs proper blood testing as early as possible. The oral glucose tolerance test (OGTT) is a gold standard to make the diagnosis of type 2 diabetes. It is used for the diagnoses of gestational diabetes too.

Procedure of the oral glucose tolerance test:

For an oral glucose tolerance test, person fasts overnight then the fasting plasma glucose is tested. After this test, the person receives 75 to 100 grams of glucose. Afterwards, blood is drawn for measurement of glucose at the intervals of 2 hours, 3 hours and so on as recommended by physician.

How reliable is the oral glucose tolerance test?

For the most reliable oral glucose tolerance test, the person should be good in health, should be in normal activity and even do not take any medicines. The classic procedure shows  how insulin acts to normalize the blood sugar level in certain time period.

In a normal person the result of oral glucose tolerance test is quite different from the diseased one. In normal condition, the glucose levels rise first and then fall quickly after taking 75 grams glucose. While, in diabetics patients, glucose level rises higher than normal and fail to return as fast as in normal. It is not evident that people with impaired glucose tolerance must have diabetes. Each year, around 1%-5% of people having impaired glucose tolerance test actually develop diabetes. Recent studies also show that person with impaired glucose tolerance may have increase risk of heart disease.

Problems with oral glucose tolerance test:

Overall, oral glucose tolerance test is not a difficult task for the subject except some problems, like;

Some feel nauseated or sweaty after drinking the glucose.

People also feel moderate pain when blood is drawing and other feel stinging sensation.

Other risks of oral glucose tolerance test are associated with blood drawn include:

 • Excessive bleeding.

 • Formation of hematoma.

 • Fainting

 • Infection

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