The test begins with a fasting blood sample, usually taken after at least 8 hours of fasting.A glucose solution (usually 75g of glucose dissolved in water) is then ingested. Subsequent blood samples are taken at intervals (commonly at 1 hour and 2 hours) after drinking the solution to track how the body responds to the glucose load.

Procedure:

• • The test begins with a fasting blood sample, usually taken after at least 8 hours of fasting.
  • A glucose solution (usually 75g of glucose dissolved in water) is then ingested.
  • Subsequent blood samples are taken at intervals (commonly at 1 hour and 2 hours) after drinking the solution to track how the body responds to the glucose load.

Risk Assessment

• Low Risk: The test is generally safe for most people.
• Potential Risks:
  • Mild discomfort from needle insertion.
  • Rare: Dizziness, nausea, or fainting due to the glucose load.
  • For pregnant women, the test could pose some risks such as dehydration or abnormal results that may need further testing.

Normal Range

• Fasting Blood Glucose: 70–99 mg/dL (3.9–5.5 mmol/L)
• 1-hour Post-Glucose: Less than 180 mg/dL (10.0 mmol/L)
• 2-hour Post-Glucose: Less than 140 mg/dL (7.8 mmol/L).

Interpretation of Results

• Normal:
  • Fasting: 70–99 mg/dL
  • 1-hour: Less than 180 mg/dL
  • 2-hour: Less than 140 mg/dL
• Impaired Glucose Tolerance (Prediabetes):
  • Fasting: 100–125 mg/dL
  • 1-hour: Above 180 mg/dL, but below 200 mg/dL
  • 2-hour: 140–199 mg/dL
• Diabetes:
  • Fasting: 126 mg/dL or higher
  • 1-hour: 200 mg/dL or higher
  • 2-hour: 200 mg/dL or higher.

Sample Type

• Blood samples are typically drawn from a vein in the arm, although in some cases, capillary blood from a fingerstick may be used for the test.