For a 3-hour GTT, what blood samples would the laboratory assistant collect?

In a 3-hour glucose tolerance test (GTT), the procedure is designed to monitor how the body processes glucose after fasting and following glucose ingestion. The correct answer includes the fasting sample, blood samples taken at 1-hour, 2-hour, and 3-hour intervals, along with a urine sample.

The rationale for including both blood and urine samples is that glucose levels are measured in the blood to assess how quickly glucose is cleared from the blood and utilized by the body's cells. The urine sample is used to check for glucosuria, which indicates how well the kidneys are managing excess glucose.

The fasting sample provides a baseline measurement of glucose levels before any glucose has been ingested, which is essential to determine how the body reacts to glucose overdoses later in the test. The sequential blood samples are needed to observe the body’s glucose metabolism over time, giving a clearer picture of how effectively insulin is functioning in response to glucose intake.

In summary, the combination of these blood samples and urine assessment provides comprehensive insights into glucose metabolism, essential for diagnosing conditions like diabetes.