OSMT (Ontario Society of Medical Technologists) Practice Exam

What is the specimen requirement for a red cell folate test?

1. 1-2 ml of whole blood drawn into an EDTA tube

2. 1-2 ml serum drawn into a red top tube

3. 3-5 ml of plasma drawn into an EDTA tube

4. 3-5 ml of serum drawn into an SST tube

The correct answer is: 1-2 ml of whole blood drawn into an EDTA tube

The specimen requirement for a red cell folate test is indeed 1-2 ml of whole blood drawn into an EDTA tube. This is because red cell folate testing is designed to measure the level of folate within red blood cells, providing an indication of the body’s folate status over the previous few months. Whole blood is essential for this test since the folate must be extracted from the red blood cells themselves, rather than from serum or plasma. The use of an EDTA tube is also critical, as EDTA acts as an anticoagulant, preventing the blood from clotting and allowing for accurate measurements of folate content within the red blood cells. In contrast, serum and plasma samples, which are mentioned in the other choices, do not provide the necessary content for assessing red cell folate levels because they reflect only the folate that may be present in the circulatory system at that moment, rather than the stored folate in red blood cells.