CPT (Certified Phlebotomy Technician) Practice Exam 2026 - Free Certified Phlebotomy Technician Practice Questions and Study Guide

The correct timing for drawing a blood sample after a glucose tolerance test (GTT) drink is 30 minutes post-ingestion. This timing allows for adequate absorption of the glucose into the bloodstream to measure how effectively the body can process glucose. The GTT is designed to test how well insulin functions and how glucose metabolism is handled by the body, so capturing this data at the 30-minute mark is critical for providing accurate results.

Drawing blood too early may not reflect the peak blood glucose levels, while waiting too long could result in levels returning to baseline, leading to misinterpretation of the results. Therefore, 30 minutes post-ingestion is established as the standard for ensuring reliable and valid test results.