Fasting Plasma Glucose test is positive when the value of elevated blood sugar level is above 140 mg/dl after an overnight fast. If the value is above 140 mg/dl on at least two occasions, it means that a person has diabetes. Normal people have fasting sugar levels that generally run between 70-110 mg/dl.

A PP or random plasma glucose level of more than 200 mg/dl indicates diabetes mellitus.A level between 140-199 mg/ dl is called "impaired glucose tolerance". A blood sugar exceeding the level of 200 mg/dl or higher generally indicates the presence of diabetes.