impaired glucose tolerance (IGT) /imperd″/ [L, impejorare, to make worse; Gk, glykys, sweet; L, tolerare, to endure] , a condition in which fasting plasma glucose levels are higher than normal but lower than those diagnostic of diabetes mellitus. In some patients this represents a stage in the natural history of diabetes, but in some people IGT either does not progress or ends, and glucose tolerance reverts to normal. Also called impaired prediabetes. See also diabetes mellitus.
