Medical Guides

How is the Fasting Blood Test Conducted?

* The subject should not consume any food or drink after midnight to the morning of the test (8 hours approximately).

* Water is permitted.

* Ask the treating doctor, whether regular morning medication can be avoided until the sample has been taken.

Interpretation: The fasting blood glucose test is interpreted as follows:

* Normal blood glucose –         below 110 mg/dl.
* Impaired fasting glucose –         between 110 and 125 mg/d1.
* Diabetes –                 126 mg/dl or above.

What is Oral Glucose Tolerance Test (OGTT)?

The OGTT measures blood glucose levels in fasting state and after a glucose challenge. Fasting glucose test detects most of the diabetes cases. However, OGTT is more sensitive in identifying people with raised blood glucose levels that first appear only after eating food or after a4P41114k glucose challenge.

* The person to be tested must be on their usual diet, exercise and routine schedule for at least 3 days prior to the test.

* The test should be carried out in the morning after fasting for 8 hours.

* 80 grams of glucose dissolved in water (for children the dose is 1.75 gm of glucose per kg of body weight up to a maximum of 80 gm) is given orally. It may be flavoured with a little lime to make it more palatable; the glucose solution should be ingested within 4-5 minutes.

* Blood is again collected 2 hours after glucose ingestion.

Interpretation of OGTT: The results of OGTT are interpreted as follows:

* Normal glucose tolerance – Blood glucose does not rise higher than 140 mg/di, two hours after the drink.

* Impaired glucose tolerance (IGT) – People with IGT have blood glucose levels that are higher than normal (the two-hour blood glucose is between 140 and 199 mg/dl.) but not high enough to say they have diabetes.

* Diabetes – Two hours blood glucose rises to 200 mg/dl or above.