When are plasma levels determined during an oral glucose tolerance test?

• A. At 1 hour, 2 hours, and 3 hours
• B. At 30 minutes, 1 hour, and 2 hours
• C. At 2 hours, 3 hours, and 4 hours
• D. At 1 hour and 2 hours only

Answer: (A)

The correct response is based on the standard procedure for conducting an oral glucose tolerance test (OGTT), which is utilized to evaluate how well a person processes glucose and to diagnose conditions such as gestational diabetes.

During an OGTT, plasma glucose levels are measured at specific intervals to assess the body's capability to manage glucose following the ingestion of a glucose solution. Typically, testing is conducted at intervals of one hour, two hours, and sometimes three hours after consumption of the glucose load. This schedule allows healthcare providers to observe how quickly and effectively glucose levels return to baseline, indicating how efficiently insulin is working in the body.

Measuring plasma levels at one hour and two hours is crucial for capturing the peak response and then the return to baseline, which can reveal important information about insulin sensitivity and beta-cell function. Three-hour assessments, while not universally used in all testing scenarios, can provide additional data for certain high-risk populations or when more comprehensive glucose regulation analysis is necessary.

In contrast, the other options suggest variations of timing that do not align with typical testing protocols, thereby lacking the comprehensive assessment necessary to accurately determine glucose tolerance in individuals.