2-Hour Glucose Tolerance Test During Pregnancy
Laboratory Tests
Obie Editorial Team
What is the 2-hour glucose tolerance test?
In some cases, the 2-hour glucose tolerance test may be used in place of the 1-hour glucose tolerance test during pregnancy, and the protocol is basically the same. You fast overnight and then go to the lab in the morning to give a blood sample. Then, you drink a 75-gram glucose solution. One hour and two hours after consumption blood draws are taken to measure the blood glucose.
If levels are higher than normal at any stage of the test, additional testing may be ordered to rule out, or definitively diagnose gestational diabetes.
The test requires at least three days of normal food consumption and activity before fasting. Smoking is not allowed during the test as results may be affected.
Normal value range
- Fasting Values: 92 mg/dL or 5.1 mmol/L
- 1-Hour Values: 180 mg/dL or 10 mmol/L
- 2-Hour Values: 153 mg/dL or 8.5 mmol/L
* Values are not affected by pregnancy
Read More
The glucose challenge test does not necessarily diagnose diabetes but it screens women who may be at risk and who may need a 3-hour glucose tolerance test or GTT.
Type 1 diabetes, commonly referred to as juvenile diabetes, is typically diagnosed in children or young adults, though diagnosis can occur in any stage of life. Of the nearly 26 million people in the United States with diabetes, only 5% have type 1 diabetes.