What is the primary purpose of the order of draw in phlebotomy?

The primary purpose of the order of draw in phlebotomy is to prevent cross-contamination of additives between different blood collection tubes. Each type of tube contains specific additives that are necessary for different tests; for example, some tubes contain anticoagulants, while others may have preservatives or clot activators. If tubes are not collected in the correct order, the additives from one tube may contaminate another, which can lead to inaccurate test results. This careful sequencing ensures that the specimens remain pure and that the laboratory can perform reliable analyses.

The order of draw is a critical protocol that helps maintain the integrity of the blood samples, thereby directly impacting the accuracy of the tests conducted on those samples. This is essential in providing proper patient care, as erroneous results could lead to misdiagnosis or inappropriate treatment.