Answer :
Final answer:
Option A. Blood culture, EDTA tubes, serum tubes. This order is important to avoid contamination and ensure valid results in tests like blood counts and serum harvesting for further analysis.
Explanation:
When performing capillary draws, the correct order of draw is a) Blood culture, EDTA tubes, serum tubes. This sequence is crucial to prevent cross-contamination and ensure the accuracy of the test results. The blood culture tube is drawn first to reduce the risk of contaminating the sample with additives found in other tubes. Next, the EDTA tube, often used for complete blood counts (CBC) or iron studies, is used where EDTA acts as an anticoagulant to prevent clotting. Serum tubes are drawn last; these tubes typically contain a clot activator and gel separator. They are used to obtain serum after the blood has clotted and the sample has been centrifuged, which explains what happens during the hour that a blood sample in the glass tube is left undisturbed; the sample clots and the serum can be harvested for analysis.
Laboratory procedures, like measuring reactions of blood samples with Anti-A or Anti-B serum, rely on the correct order of draw to maintain test integrity. When a capillary tube is used to collect blood by capillary action, it's vital to fill and keep the tubes in a specific order, just as it is important to add reagents in the correct sequence when working with blood typing assays. As instructed, all these procedures help minimize pre-analytical errors in laboratory diagnostics.
