Maintanence of Glucose Level

Fasting plasma Glucose is defined as no caloric intake for at least 8 hrs.
Normal Values < 100mg/dl
Impaired Fasting Glucose is defined as plasma Glucose between 100 to 126 mg/dl
In Diabetes fasting plasma glucose is > 126mg/dl 
Post Prandial (post lunch) plasma glucose is 2hrs after beginning of meal .Normal Values <140 mg/dl
Impaired glucose tolerance is defined when plasma glucose values are between 140 to 200mg/dl.

At present post prandial blood sugar values  after 1 hr and 1and ½  hrs also are being evaluated for change in treatment .For diagnosis of Diabetes post-meal or post 75gm glucose challenge values >200mg/dl.

Fasting and post Prandial plasma glucose on the different days are also accepted for diagnosis and treatment of diabetes .