Glucose tolerance test?

The clinical diagnostic test for diabetes mellitus is usually a venous fasting blood glucose measurement. When venous fasting blood glucose <5.0mmol/L (basis), diabetes can be ruled out; when venous fasting blood glucose >7.0mmol/L and there are clinical symptoms, then the diagnosis of diabetes can be made; and when the venous fasting blood glucose is between 5.5 and 7.0mmol/L and diabetes is suspected, then a further glucose tolerance test should be done --- OGTT.

The OGTT is an oral glucose loading test, which is used to understand the body's ability to regulate blood glucose after eating glucose. The OGTT test allows for early detection of abnormal glucose metabolism and early diagnosis of diabetes.

The oral glucose tolerance test (OGTT) is a glucose loading test to understand the function of pancreatic β-cells and the body's ability to regulate blood glucose, and it is a confirmatory test for the diagnosis of diabetes mellitus, which is widely used in clinical practice.

Because the test involves taking glucose orally to increase blood glucose levels, it is not appropriate to do this test when a patient has been diagnosed with diabetes, so it is only performed when blood glucose is higher than normal and does not meet the criteria for diagnosing diabetes. It may need to be repeated in patients in the acute phase of other diseases to clarify the diagnosis of diabetes.