When performing a capillary blood draw on an infant, which tubes should be drawn first?

In the context of a capillary blood draw, the correct choice pertains to the lavender tubes, which are typically used for complete blood counts (CBC) and other hematological tests. These tubes contain an anticoagulant called EDTA that preserves the integrity of the blood sample, preventing clotting. When drawn first, they ensure that any contamination from subsequent tubes, which may contain different additives, does not affect the results of the hematology tests.

Blood draws in a specific order are important to reduce the risk of sample contamination and ensure accurate laboratory results. For instance, blue tubes are often used for coagulation studies and contain sodium citrate, while green tubes may contain heparin for various other tests. If these tubes were drawn before the lavender tubes, the additives could interfere with the results of the tests designed for EDTA. Therefore, starting with the lavender tubes is aligned with best practices for specimen collection in order to maintain the quality and reliability of the blood tests being performed.