Which type of tube should be collected first for dermal blood samples?

When collecting dermal blood samples, the appropriate first tube to fill is typically the lavender top tube. This tube contains EDTA, an anticoagulant that is essential for hematological tests, as it preserves the integrity of the blood samples by preventing clotting. Collecting this tube first ensures that the samples can be analyzed for various blood components, such as complete blood counts, without the interference of clotting factors.

The order of draw in phlebotomy is important not only for minimizing contamination but also for ensuring the accuracy of the tests conducted on the blood samples. While other tubes serve different purposes (for example, the red top tube is often used for serum tests as it does not contain additives, and the light blue top tube is used for coagulation studies), initiating the collection with the lavender top tube is critical for maintaining proper test results for hematological analysis. Therefore, collecting the lavender top tube first aligns with best practices in blood specimen collection protocols.