21 Dec 2014

Screening for gestational diabetes mellitus - Glucose challenge test and glucose tolerance test

Gestational diabetes means diabetes first detected during the present pregnancy. Usually occur during the later half of pregnancy. Its detection and treatment is important because this can result in increased birth weight of fetus and complication during delivery.

Screening for diabetes during pregnancy.
Glucose challenge test (GCT)

How it is done ?
Patient is given 50 gms of oral glucose, as sugar syrup (dissolved in about 150 ml of water) to drink. This test is done without regard to time or last meals.
Usually done between 24 to 28 week of pregnancy.
A plasma glucose value 140 mg% or whole blood value 130 mg% is considered as cut off value and indication for  Glucose tolerance test.


Glucose tolerance test or (GTT)
Glucose tolerance test is done after taking 100 gm oral glucose (75 gm glucose as per WHO recommendation). Fasting blood sugar and blood sugar first ,second and third hour after 100 gm glucose is taken. If done after intake of 75 gms of oral glucose, fasting and 2 hour blood sugar  is taken.
Interpretation of GTT
Criteria for diagnosis of gestational diabetes with 100 gm oral glucose tolerance test.

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