Diabetes blood Test - Glucose tolerance test:

This is a superb test to evaluate the metabolism of dietary carbohydrates in the body.

After taking the evening meal on the day prior to the test-day, the person should not eat or drink anything. He should not even smoke. On the test-day, the person should go for the test early in the morning, with an empty stomach.

First of all, urine and blood samples are collected to determine fasting urine-sugar and blood-sugar. After overnight fasting, your blood will be tested for glucose, then you are given a certain amount of glucose to drink, then for every 30 minutes, your blood will be retested to see how your body is handling the glucose. Simultaneously, your urine will also be tested.

The following characteristics are seen in a healthy person during this test:

Fasting blood-sugar level is less than 120 mg% (many a time 100 mg%).
The amount of glucose in the blood rises to a maximum value in 30 to 60 minutes after the meal. This maximum value is not more than 160 mg%.
Two hours after the meal, the blood-glucose level comes down to the fasting level.

Diabetics, on the other hand, show the following characteristics during this test :

Fasting blood-sugar level is equal to or greater than 140 mg%. However, in early or mild diabetes the value obtained may be a little lower, say 120 mg %.
After the meal, the concentration of blood-sugar takes more than an hour to reach the maximum value. This maximum value is equal to or greater than 200 mg %. However in early or mild diabetes the maximum value obtained may be180 mg%.
Two hours after the meal, the amount of blood-glucose is still quite high (140 mg% or more) as compared to normal.

Normal:
Fasting Value less than 120 mg
Maximum Value less than 160 mg
Value two hours after consuming glucose less than 120 mg

Early (borderline):
Fasting value 120 to 140 mg
Maximum value 160 to 180 mg
Value two hours after consuming glucose 120 to 140 mg

Established Diabetes:
Fasting Value more than 140 mg
Maximum value 200 or more mg
Value two hours after consuming glucose more than 140 mg