FAQs about prediabetes?What is Impaired Glucose Tolerance (IGT)?

Impaired glucose tolerance (IGT) is a term to describe when a person has elevated blood sugar (blood glucose) in response to eating.

IGT is diagnosed when blood sugar levels are not normal, but not high enough to be classified as diabetes.

IGT is one reason why a person may be diagnosed with pre-diabetes. IGT carries an increased risk of developing type 2 diabetes.


Oral Glucose Tolerance Test Ranges


(except during pregnancy);
(per American Diabetes Association Guidelines)

2 Hours after drinking 75 grams of glucose Indication
Less than 140, or 7.8 mmol/L Normal glucose tolerance, not diabetic
From 140 to 200 mg/dL, or 7.8 to 11.1 mmol/L Impaired glucose tolerance (IGT), or Pre-diabetes
Over 200 mg/dL, or 11.1 or higher on more than one occasion Type 2 Diabetes (an OGTT would never be given to a person suspected of having type 1 diabetes)

It is important to know the difference between high and low blood sugars so you can treat them properly

How to Improve Glucose Tolerance

Lifestyle changes including weight loss and an exercise program, as well as oral medications can improve glucose tolerance.

There is no cure for type 2 (or type 1) diabetes, but pre-diabetes can often be completely reversed with proper medical intervention and changes in lifestyle.