American Medical Certification Association (AMCA) Phlebotomy Practice Exam

If a doctor orders a CBC Test, Comprehensive Metabolic Panel, PT Test, and a set of Blood Cultures, what would the order of draw be?

1. Light Blue, SST, Lavender, BC

2. BC, Executive Top, Light Blue, Lavender Top

3. BC, Light Blue, SST, Lavender Top

4. SST, BC, Lavender, Light Blue

The correct answer is: BC, Light Blue, SST, Lavender Top

The correct order of draw for the specified tests is crucial for ensuring accurate laboratory results and minimizing the risk of contamination between samples. In the scenario provided, the blood cultures (BC) should always be drawn first. This is because they are highly sensitive to contamination and drawing them initially helps to ensure that any bacteria present in the sample represents what’s in the bloodstream and is not from external sources. Following the blood cultures, the light blue top tube should be drawn next. This tube is used for coagulation studies, and it contains sodium citrate, which can affect results if contaminated by other additives from different tubes. Next in the order is the serum separator tube (SST), which is used for the comprehensive metabolic panel. This tube provides a clot activator and gel that separates the serum from the blood cells after centrifugation. Ensuring this tube is drawn after the light blue tube helps prevent any interference from anticoagulants contained in the light blue tube. Finally, the lavender top tube is used for the complete blood count (CBC) and contains EDTA, which is also an anticoagulant. Drawing this last ensures that any potential contamination from the previous tube does not affect the CBC results. This sequence aligns with established phlebotomy