APIC243882242 - CME/CMLE - Contamination in Blood Collection and the Effects on Laboratory Testing-APIC243882242

APIC243882242 - Educational Activity

Pdf Summary

This educational commentary by Corey Swackhammer, MS, MLS(ASCP)CM MBCM, examines contamination issues in blood collection and their impacts on laboratory testing accuracy. It addresses common contamination types, prevention strategies, the rationale behind the established order of draw for blood collection tubes, and effects on specific analytes.<br /><br />Key contamination sources include transfer of tube additives between tubes, hemolysis, environmental exposure, and microbial contamination in sterile collection tubes. The pre-preanalytic phase—when non-laboratory personnel often collect samples—poses the highest risk for errors affecting sample integrity. Hence, interdisciplinary training is essential to ensure adherence to proper procedures.<br /><br />The commentary emphasizes the strict order of draw (sterile tubes first, followed by light blue, serum, heparin, EDTA, gray, then yellow ACD tubes) to prevent additive carryover. For example, EDTA contamination in serum tubes can cause falsely elevated potassium (pseudohyperkalemia), posing serious clinical risks if misinterpreted. Similarly, clot activators in serum tubes must not contaminate sodium citrate tubes used for coagulation testing to avoid falsely shortened clotting times.<br /><br />Regarding coagulation samples, recent guidelines have relaxed the need for discard tubes before sodium citrate tubes for common assays but recommend their use when a butterfly collection set with tubing is used, to maintain accurate blood-to-anticoagulant ratios.<br /><br />Trace element testing requires special attention to prevent environmental contamination due to their low physiologic levels and ubiquitous presence in the environment; dedicated tubes and controlled lab environments are necessary. Blood cultures demand strict aseptic technique and proper order (aerobic before anaerobic bottles) to minimize contamination and avoid misleading results that could harm patient treatment.<br /><br />Additional contamination risks arise from hemolysis caused by improper needle size, technique, or collection site (e.g., near IV lines or edematous areas). The commentary advises against open collection systems and transferring blood between tubes, stressing that aliquoting should be done carefully and tubes only uncapped by lab personnel to prevent cross-contamination.<br /><br />In conclusion, maintaining specimen integrity through strict adherence to standardized procedures, including order of draw, closed systems, adequate cleansing and drying, and appropriate handling, is critical to producing accurate, clinically meaningful laboratory results and safeguarding patient care.

Keywords

blood collection contamination

order of draw

additive carryover

hemolysis

pre-preanalytic phase

coagulation testing

trace element testing

blood culture aseptic technique

sample integrity

laboratory testing accuracy