Impaired glucose tolerance is a condition in which an individual has higher than normal levels of glucose in the blood upon fasting or following a carbohydrate-rich meal or ingestion of a glucose test solution but not high enough to be diagnostic of diabetes mellitus.

IGT is diagnosed when the fasting level is less than 7.0 mmol/L and the two-hour level is 7.0-11.1 mmol/L. People with IGT have a high risk of progression to type 2 diabetes over time

Unit 1,

Reference: Oxford Concise Colour Medical Dictionary (7th Edition, Kindle Edition) Oxford University Press 2020 ISBN-13: 978-0198836629, p1553