The Diagnostic Criteria for Diabetes Mellitus

The Diagnostic Criteria for Diabetes Mellitus

The new criteria

            The diagnostic criteria for diabetes mellitus have been modified form those previously recommended by the NDDG or WHO.

            Three ways to diagnose to diagnose diabetes are possible and must be confirmed, on a subsequent day by any one of the three methods mentioned.

            For example, one instance of symptoms with casual plasma glucose value of >200mg/dl, confirmed on a subsequent day by 1) FPG (fasting plasma glucose) >126mg/dl. An 2) OGTT (oral glucose tolerance test) with the 2-hour post load value of >200 MG/DL, or 3) symptoms with a casual plasma glucose >200mg/dl, warrants the diagnosis of diabetes.

            For epidemiological purpose, estimates of diabetes prevalence and incidence should be based on an FPG (fasting plasma glucose) > 126mg/dl.

            This recommendation is made in the interest of standardization and also to facilitate field work, particularly where OGTT may be difficult to perform and where the cost and demands on the participant’s time may be excessive.

            This approach will lead to slightly lower estimates of prevalence than would be obtained from the combined use of FPG and OGTT.

            The expert committee recognized an intermediate group of subjects whose glucose levels, although not meeting the criteria for diabetes, are nevertheless too high to be considered normal. Thus group called the IFG (Impaired fasting glucose) is defined as having FPG levels of >110mg/dl, but 126<mg/dl or 2-hour values in the OGTT of >140mg/dl but < 200 mg/dl.

Thus the categories of the FPG values are as follows.

            FPG < 110mg/dl = normal fasting glucose

            FPG > 110 and < 126mg/dl = IFG

            FPG > 126 mg/dl = provisional diagnosis of diabetes.

The corresponding categories when OGTT is used are as following.

2-hour post load glucose (2h PG), ≤ 140mg/dl – normal glucose tolerance

2 h PG > 140 and < 200 mg/dl – IGT

2-hPG > 200mg.dl = provisional diagnosis of diabetes.

Criteria for diagnosis of diabetes mellitus

1. Symptoms of diabetes plus casual plasma glucose concentration 200mg/dl (11.1mmol/L). Casual is defined as any time of day without regard to time since last meal. The classic symptoms of diabetes include polyuria, polydipsia, and unexplained weight loss.
2. FPG >126mg/dl (7.0mmol/L). Fasting is defined as no caloric intake for at least 8 hours.
3. 2-h PG>200 mg/dl during an OGTT. The test should be performed described by the WHO, using a glucose containing the equivalent of 75 grams of anhydrous glucose dissolved in water.

            In the absence of unequivocal hyperglycemia with acute metabolic decompensation, these criteria should be confirmed by repeat testing on different day. The third measure of OGTT is not recommended for routine clinical use.

            Comparison on National Diabetes Date Group (NDDG), world Health Organization (WHO), and American Diabetes Association (ADA), criteria for classification of categories of glucose intolerance.