Doctors can determine whether a patient has a normal metabolism, prediabetes or diabetes in one of three different ways – there are three possible tests:

• The A1C test
  – at least 6.5% means diabetes
  – between 5.7% and 5.99% means prediabetes
  – less than 5.7% means normal

• The FPG (fasting plasma glucose) test
  – at least 126 mg/dl means diabetes
  – between 100 mg/dl and 125.99 mg/dl means prediabetes
  – less than 100 mg/dl means normal
  An abnormal reading following the FPG means the patient has impaired fasting glucose (IFG)

• The OGTT (oral glucose tolerance test)
  – at least 200 mg/dl means diabetes
  – between 140 and 199.9 mg/dl means prediabetes
  – less than 140 mg/dl means normal
  An abnormal reading following the OGTT means the patient has impaired glucose tolerance (IGT)