The American Journal of Nursing (AJN)Reducing Blood Culture Contamination Rates in the ED

✅ Clinical Decision Support

A $0.25 sterile diversion tube cut blood culture contamination rates by 85% in an ED quality improvement project, dropping from 2.9% to 0.4% in two months across 1,904 cultures. Contaminated cultures cost an average of $10,921 per patient, driven largely by unnecessary antibiotic treatment and extended length of stay. Single-site data from a California community hospital limits generalizability, but the intervention is low-cost, low-complexity, and immediately replicable.

Clinical Considerations

• The diversion technique works by discarding the first 1.5 to 2 mL of blood before filling culture bottles, preventing skin-dwelling organisms from entering the sample
• Coagulase-negative staphylococci accounted for 52% of contaminants, the most common false-positive organisms in bedside blood culture draws
• Staff compliance reached 79.5% in the second month after weekly feedback sharing, up from 52% in month one, suggesting audit-and-feedback loops accelerate adoption
• False positives trigger unnecessary vancomycin courses, repeat labs, and an average two additional inpatient days, all preventable with proper draw technique

Practice Applications

• Discard the first 1.5 to 2 mL of blood into a sterile diversion tube before inoculating culture bottles on every blood culture draw
• Cleanse the venipuncture site with 70% alcohol in a circular motion for 30 seconds before applying CHG, not CHG alone
• Never touch the skin after disinfection; if contact occurs, restart the prep sequence
• Ask your manager to track unit contamination rates and share them with staff — weekly feedback was directly linked to compliance improvement in this study