Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

When should blood be collected for a 2-hour postprandial glucose test?

1. 2 hours after testing

2. 2 hours after the next meal

3. 2 hours before the next meal

4. Within 2 hours after arrival at the lab

The correct answer is: 2 hours after the next meal

The correct timing for collecting blood for a 2-hour postprandial glucose test is crucial for accurately assessing a person's glucose metabolism in response to food intake. The test measures blood glucose levels specifically 2 hours after the patient has consumed a meal. This is important because it allows healthcare providers to evaluate how well the body manages blood sugar levels following carbohydrate consumption. The purpose of a postprandial glucose test is to determine how effectively insulin is able to regulate blood glucose levels after a meal. By timing the blood draw precisely 2 hours after the individual's meal, it provides an insight into how their body is responding to the glucose load from that meal. This is particularly useful in diagnosing diabetes or assessing glycemic control in individuals with diabetes. Choosing to collect blood 2 hours after the next meal or at any other time would not accurately reflect the blood sugar response to the meal that was eaten for the test, thereby undermining the test's validity. Therefore, collecting blood 2 hours after the meal rather than before or after another unrelated meal is the appropriate timing for this test.