Diagnostic Criteria for Diabetes

Diagnostic Criteria for Diabetes

The diagnostic criteria for diabetes are as follows:

  • Two blood sugar values above 126 mg/dl in a fasting test, whereby the fasting period was at least 8 hours; 
  • One blood sugar value above 200 mg/dl, two hours after 75 grams of oral glucose ingestion;
  • One occasional blood sugar level above 200 mg/dl in an individual with classic hyperglycemia symptoms (severe thirst, urinating in large quantities and associated weight loss). 

The American Diabetes Association also considers one value of hemoglobin A1c (laboratory value representing the average blood glucose value over the past three months) equal to or above 6.5% as a diagnosis of diabetes. However, this criterion has not yet been acknowledged by the European Association for the Study of Diabetes. 

It should be noted that the valid values for diagnostic purposes refer to venous blood samples and not capillary blood glucose. This sample should not be taken on stressful occasions (such as during periods of infection, trauma or emergency observation). 

There are also values which represent a pre-diabetes condition; although not diagnosed as diabetes, the pre-diabetes state represents an increased risk for the development of diabetes and is associated with an increased risk of cardiovascular disease. Alterations representative of a pre-diabetes condition includes: 

  • Changes in blood glucose during fasting; blood glucose values in a fasting test above 100 mg/dl, but below 126 mg/dl;
  • Intolerance to oral glucose; values above 140 mg/dl, but below 200 mg/dl, following 75 grams of oral glucose ingestion.