NHA Phlebotomy Certification Practice Exam

Which laboratory test typically requires fasting prior to collection?

1. Glucose tolerance test

2. Complete blood count

3. Liver function tests

4. Electrolyte panel

The correct answer is: Glucose tolerance test

Fasting is crucial for a glucose tolerance test because it measures how well your body processes glucose. During the test, the individual is typically required to avoid food and drink (except water) for a specified period, usually 8-12 hours before the test. This preparation helps ensure that the results are not skewed by recent food intake, which could artificially raise blood glucose levels and provide misleading information about the body’s insulin response and overall glucose metabolism. In contrast, other tests listed do not require fasting. A complete blood count can be performed at any time and will not be significantly affected by recent meals. Liver function tests also do not necessitate fasting, as they assess various enzyme levels and substances in the blood that reflect liver health regardless of food intake. Similarly, an electrolyte panel can be conducted with or without fasting since the levels of electrolytes such as sodium, potassium, and calcium are not influenced by recent dietary consumption in a way that would significantly affect test results. Understanding the specific requirements for each test is key to accurate lab results and patient care.