American Medical Certification Association (AMCA) Phlebotomy Practice Exam

How many tubes are needed for a 3-hour glucose tolerance test?

1. 2 Gray Tube Tops

2. 3 Gray Tube Tops

3. 4 Gray Tube Tops

4. 5 Gray Tube Tops

The correct answer is: 4 Gray Tube Tops

A 3-hour glucose tolerance test typically requires four tubes to accurately assess the patient’s glucose levels at various intervals. This test is designed to measure how well the body processes glucose over a designated period. Initially, a fasting blood sample is taken to establish a baseline glucose level. Following this, the patient consumes a glucose solution, and additional blood samples are collected at regular intervals, usually at 1 hour, 2 hours, and finally at the 3-hour mark after ingestion. Each of these scheduled intervals necessitates separate blood samples, leading to the requirement of four tubes in total. Choosing the correct number of tubes is crucial for ensuring accurate test results and patient safety, as insufficient sampling can lead to incomplete data and potentially misdiagnosis of conditions such as diabetes.