What is this test?
An OGTT measures how blood glucose changes after a standardized oral glucose drink. It can detect impaired glucose regulation or diabetes that is not apparent from one fasting value.
Why might it be ordered?
- To investigate possible diabetes or impaired glucose tolerance when clinically appropriate.
- For pregnancy-related glucose testing under the maternity protocol.
What sample is needed?
Blood is collected before and at protocol-defined times after the glucose drink. The number and timing of samples depend on the exact ordered protocol.
How should you prepare?
Confirm the laboratory protocol in advance. Maintain your usual carbohydrate-containing diet and normal activity for the preceding days, then complete the required overnight fast. During the test, remain seated, do not eat, smoke or exercise, and drink only water if allowed. Ask about medicines; do not change them on your own.
How should you understand the result?
Thresholds differ between non-pregnant and pregnancy protocols and by sampling time. If you vomit or a sample is late, tell the staff because the test may be invalid.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.