The sequence in which blood collection tubes are filled during venipuncture is a critical aspect of laboratory medicine. Deviations from the established procedure can introduce inaccuracies into test results, potentially leading to misdiagnosis and inappropriate treatment. This standardized methodology minimizes the risk of cross-contamination between additives present in different collection tubes.
Adhering to the prescribed fill order reduces the likelihood of additive carryover, preventing interference with subsequent analyses. For example, EDTA, an anticoagulant present in lavender-top tubes, can artificially lower calcium levels if it contaminates a downstream tube intended for serum calcium determination. Similarly, clot activators in serum tubes can initiate coagulation prematurely in tubes requiring whole blood or plasma. The implementation of a defined order minimizes these preanalytical errors, enhancing the reliability and validity of diagnostic information. This practice has evolved over time, refined by scientific investigation and clinical experience to optimize patient safety and test accuracy.
