What is the purpose of the order of draw in blood collection?

The purpose of the order of draw in blood collection is crucial in maintaining the integrity of the samples collected. By following a specific sequence, healthcare professionals can prevent cross-contamination of additives between different collection tubes. Each tube is designed to contain specific additives that can affect test results; for example, tubes with anticoagulants should not come into contact with serum tubes because the presence of anticoagulants in a serum sample can lead to inaccurate lab results.

For instance, if a tube containing EDTA (an anticoagulant) is drawn before a serum tube, traces of EDTA can leach into the serum tube, potentially interfering with serum tests. Therefore, adhering to the established order of draw minimizes the risk of such contamination, ensuring that each sample remains pure and accurate, which is essential for obtaining reliable laboratory results.