Medical Assistant Certification (MAC) AMCA Practice Exam

Which laboratory test would NOT typically use a lavender tube for specimen collection?

1. Hemoglobin levels

2. Platelet count

3. Thyroid function tests

4. White blood cell count

The correct answer is: Thyroid function tests

The lavender tube, also known as the EDTA tube, is primarily used for hematology tests and other tests requiring whole blood or plasma. It contains the anticoagulant EDTA, which prevents blood from clotting and allows the analysis of various blood components. Thyroid function tests are typically performed using serum samples, which require blood to clot before it is centrifuged to separate the serum from the cells. This means that a red-top tube, which does not contain any anticoagulants and allows liquid blood to clot, is more appropriate for these tests. In contrast, hemoglobin levels, platelet counts, and white blood cell counts all generally utilize the lavender tube. These tests require whole blood or plasma to evaluate the blood's cellular components, making the lavender tube the suitable choice for these specific analyses.