Why is following the order of draw crucial in blood collection?

Following the order of draw is crucial in blood collection primarily to prevent contamination of specimens. Each type of blood collection tube contains additives that are specifically designed to facilitate different tests. If tubes are filled in the wrong order, these additives can leach into the blood samples, leading to contamination that compromises the integrity of the samples. For example, additives from a tube designed for coagulation studies could affect the results of a chemistry test if filled incorrectly. Adhering to the correct sequence minimizes the risk of cross-contamination, thus ensuring that the samples are suitable for accurate testing.

While maintaining sample temperature, ensuring test accuracy, and saving time are important aspects of the blood draw process, they are secondary to the primary goal of preventing contamination. Contamination can lead to erroneous results, which can adversely affect patient diagnosis and treatment. Therefore, the order of draw is established as a standard practice to safeguard the reliability of laboratory testing outcomes.