Testing Terminology:
(1) casual glucose concentration: performed any time during the day without regard to time since the last meal
(2) fasting plasma glucose concentration: no caloric intake for at least 8 hours
(3) oral glucose tolerance test: performed using WHO guidelines using a solution containing the equivalent of 75 grams (anhydrous) glucose dissolved in water. This is not recommended for routine clinical use.
Diabetes Mellitus
Diabetes Mellitus is considered present if
(1) one or more of the following criteria is present AND
(2) one of the following:
(2a) unequivocal hyperglycemia and acute metabolic decompensation is present
(2b) presence of one or more criteria on repeat testing on a subsequent day.
Criterion 1 – both of the following:
(1) symptoms of diabetes (polyuria, polydipsia, unexplained weight loss), AND
(2) casual plasma glucose concentration >= 200 mg/dL (>= 11.1 mmol/L)
Criterion 2: fasting plasma glucose concentration >= 126 mg/dL (>= 7.0 mmol/L)
Criterion 3: A 2 hour plasma glucose >= 200 mg/dL during an oral glucose tolerance test performed as described by WHO
Impaired Glucose Homeostasis
Impaired fasting glucose (IFT): fasting plasma glucose concentration >= 110 mg/dL and < 126 mg/dL
Impaired glucose tolerance (IGT): A 2 hour plasma glucose >= 140 mg/dL and < 200 mg/dL during an oral glucose tolerance test performed as described by WHO.
Since the oral glucose tolerance test cutoff of 140 mg/dL at 2 hours after glucose load will identify more people as having impaired glucose homeostasis than the fasting glucose cutoff of 110 mg/dL, the test used should always be reported.
Normal Glucose Homeostasis
Normal fasting glucose: fasting plasma glucose concentration < 110 mg/dL
Normal glucose tolerance: A 2 hour plasma glucose < 140 mg/dL during an oral glucose tolerance test performed as described by WHO
