PLAB Endocrinology Practice Exam 2025 – All-In-One Resource to Master Your Exam Success!

In an oral glucose tolerance test (OGTT), a venous plasma glucose level between 7.8-11.0 mmol/L, measured 2 hours after glucose intake, is classified as indicating impaired glucose tolerance (IGT). This range reflects transitional states of glucose metabolism between normal and diabetic levels.

To understand the importance of this threshold, the parameters for diagnosing diabetes and impaired glucose tolerance are defined by the World Health Organization and are widely accepted in clinical practice. Normal glucose tolerance is identified when plasma glucose levels are less than 7.8 mmol/L two hours post-glucose ingestion. A reading equal to or greater than 11.1 mmol/L is indicative of diabetes mellitus. Levels between 7.8-11.0 mmol/L signal IGT, where the body's ability to manage glucose is compromised but is not yet at the diabetic level.

Recognizing the ranges is critical in managing patients who may be at risk for developing type 2 diabetes. Screening for IGT allows for timely intervention, potentially preventing the progression to diabetes through lifestyle modifications or medical management.