Purpose:
The Glucose Tolerance Test (GTT) assesses how well the body processes glucose, commonly used to diagnose conditions like diabetes and gestational diabetes.

Overview:

• Procedure: Blood glucose levels are measured before and at specific intervals after consuming a glucose-rich drink (usually 75g).
• Indication: Typically performed when the first GTT yields borderline or abnormal results, or to monitor conditions like impaired glucose tolerance.

Risk Factors for GDM:

• • Obesity or being overweight before pregnancy
  • Previous history of gestational diabetes in a prior pregnancy
  • Family history of diabetes (especially in first-degree relatives)
  • Age over 25 years
  • Polycystic ovary syndrome (PCOS)
  • Ethnicity (higher risk in Hispanic, African-American, Native American, South or East Asian, or Pacific Islander women)
  • Previous delivery of a large baby (over 9 pounds or 4 kilograms)
  • Unexplained stillbirth or a miscarriage

Purpose of the Test: The GTT-3 is used when the initial screening test (often the 1-hour glucose challenge test) is positive. It helps to confirm or rule out the diagnosis of gestational diabetes.

The normal values for the 3-hour GTT are:
Fasting: < 95 mg/dL (5.3 mmol/L)
1 hour: < 180 mg/dL (10.0 mmol/L)
2 hours: < 155 mg/dL (8.6 mmol/L)
3 hours: < 140 mg/dL (7.8 mmol/L)
Diagnosis of GDM: Gestational diabetes is typically diagnosed if two or more of these values are exceeded.

Normal Results: If all the glucose levels are within the normal range, the patient does not have gestational diabetes.
Abnormal Results: If two or more of the glucose measurements are above the normal range, gestational diabetes is diagnosed.
Borderline Results: If only one value is abnormal, the test may need to be repeated, or the patient may be monitored more closely.

Blood Samples: Venous blood samples are used for glucose measurement in the GTT-3. The blood is typically drawn from the arm.