What is the correct order of draw for blood collection tubes?

The correct order of draw for blood collection tubes is essential to avoid contamination of samples and ensure accurate laboratory results. The correct sequence is primarily based on the type of additives present in the tubes and the potential for contamination between them.

In this context, Yellow tubes, typically used for cultures and blood banking, are drawn first to reduce the risk of contamination from anticoagulants that could interfere with the growth of bacteria in culture. Following this, Light Blue tubes, which contain sodium citrate for coagulation studies, are drawn next since they must be filled to the correct ratio of blood to anticoagulant to maintain accuracy.

Red tubes, which are often used for serology and chemistry tests and typically do not contain any additives, come after the anticoagulant tubes to prevent any carryover of anticoagulants. Green tubes, containing heparin, are drawn next for tests requiring plasma samples. Lavender tubes, which contain EDTA used for hematology tests, follow the green tubes to maintain separation of different types of samples subsequently. Finally, Gray tubes, containing additives like fluoride that are used for glucose testing, should be the last to ensure their specific purpose is not compromised by other chemicals present in the preceding tubes.

This order helps maintain the integrity of each