Diabetes Mellitus diagnosis

Diabetes mellitus commonly referred to as diabetes is a disease characterized by high blood glucose levels.


Criteria for the diagnosis of diabetes

  1. A1C(previously known as HbA1c) ≥6.5%.


  1. Fasting Plasma Glucose ≥126 mg/dl (7.0 mmol/l).

Fasting is defined as no caloric intake for at least 8 h.


  1. Two-hour plasma glucose ≥200 mg/dl (11.1 mmol/l) during an OGTT.

The test should be performed using a glucose  load containing the equivalent of 75 g anhydrous glucose dissolved in water.


  1. In a patient with classic symptoms of hyperglycemia (frequency of urination, increased thirst and apetite) or hyperglycemic crisis, a random plasma glucose ≥200 mg/dl (11.1 mmol/l)

 In the absence of unequivocal hyperglycemia, result should be confirmed by repeat testing.


Type 1  diabetes – results from beta cell destruction, usually leading to  absolute insulin deficiency

Type 2 diabetes – results from a progressive insulin  secretory defect on the background of insulin resistance

Other specific types of diabetes due to other causes, e.g.,  genetic defects in beta cell function, genetic defects in insulin action,  diseases of the exocrine pancreas (such as chronic panreatitis), and drug or  chemical-induced diabetes (such as in the treatment of AIDS or after organ  transplantation)

Gestational diabetes mellitus (GDM) – diabetes diagnosed  during pregnancy


Prediabetes – Before people develop type 2 diabetes, they  almost always have “prediabetes”—blood glucose levels that are higher than  normal but not yet high enough to be diagnosed as diabetes.  There are three  different tests your doctor can use to determine whether you have  prediabetes:
•    The A1C test
•    The fasting plasma glucose test  (FPG)
•    The oral glucose tolerance test (OGTT)