A 2-hour postprandial blood sugar (glucose) test measures the blood sugar exactly 2 hours after eating a meal. Blood sugar tests may be used to check for diabetes and to see how treatment for diabetes is working.

Normally, before age 50, blood sugar levels should rise no higher than 140 milligrams per deciliter (mg/dL) 2 hours after eating a meal. Healthy adults increase their blood sugar levels by 10 mg/dL for every 10 years of life after age 50. For example, at age 60, the blood sugar level should be less than 150 mg/dL. And at age 70, it should be less than 160 mg/dL.

Diabetes may be diagnosed if the 2-hour postprandial blood sugar level is higher than normal for a person's age. This is true especially if the test on two different days gives the same results and the person has symptoms of diabetes.