Oral Glucose Tolerance Test

 

Women who have a blood sugar level greater than 140 mg/dl (7.8 mmol/l) on their 50 gram glucose test may have gestational diabetes during pregnancy, and require a follow-up test called a 3-hour oral glucose tolerance test (OGTT).

The OGTT requires dietary preparation. For three days prior to the test, 150 grams of carbohydrates should be consumed daily. Then a fasting period of 10 to 14 hours before the test is required; only water is allowed during this time. Because of the fasting component, the OGTT is usually performed first thing in the morning in a doctors office or outpatient lab. An initial blood sample is drawn to measure fasting blood glucose levels, and then the patient is given 100 grams of a glucose drink (the same type as that given in the glucose challenge) to consume. After that, blood samples are drawn every hour for 3 hours and blood glucose levels are measured.

The American Diabetes Association sets the following guidelines for results from the OGTT:

 

  • Fasting Blood Glucose Level95 mg/dl (5.33 mmol/l)
  • 1 Hour Blood Glucose Level140 mg/dl (7.8 mmol/l)
  • 2 Hour Blood Glucose Level120 mg/dl (6.7 mmol/l)

If two or more blood sugar levels are higher than the levels indicated, gestational diabetes is diagnosed.

SOURCE:

1 - American Diabetes Association. ADA Standards of Medical Care in Diabetes?2010. Diabetes Care, Volume 33, Supplement 1, January 2010.

Reviewed by Francine Kaufman, MD. 4/10

Last Modified Date: May 24, 2013

All content on dLife.com is created and reviewed in compliance with our editorial policy.

Sign up for FREE dLife Newsletters

dLife Membership is FREE! Get exclusive access, free recipes, newsletters, savings, and much more! FPO

Congratulations!
You are subscribed!
Congratulations!
You are subscribed!
Congratulations!
You are subscribed!
119 Views 0 comments
by Chris Stocker
If you listen closely, you may hear the sound of 25 million Americans with diabetes rejoicing today. In a revolutionary movement, the FDA has given 510(k) approval on Abbott's HbA1C test which is expected to help millions of Americans with Type 1 or 2 diabetes or those at risk. Abbott's ARCHITECT Clinical Chemistry Hemoglobin A1C (HbA1C) test is a dramatic shift in diabetes diagnosis and monitoring. Instead of the HbA1C tests performed at a laboratory and constituted as blood work, the...