Use of an initial specimen diversion device (ISDD) in blood samples obtained from 971 emergency department (ED) patients at a single institution lowered the rate of blood culture contamination in comparison to the standard procedure from 1.78% to 0.22% without compromising detection of true bacteremia and candidemia (Clin Infect Dis 2017;65:201–5). The findings might “justify abandonment of the current practice of performing [two] separate venipunctures (in order to better rule out contamination), which would result in improved patient satisfaction and healthcare provider safety (fewer venipunctures),” according to the authors.
Despite efforts to curb it, blood culture contamination persists, with rates ranging from 0.6% to 6.0%. False-positive blood cultures lead to many negative consequences, including higher laboratory costs, greater use of antibiotics, extended hospitalizations, and increased patient risks from antibiotic exposure. In addition to standard phlebotomy-related skin disinfectant procedures, hospitals use various strategies to limit blood culture contamination.
Blood banks already commonly use ISDDs to minimize microbial contamination in blood products, but these devices have not been widely adopted in regular clinical care. The authors sought to test in an ED setting how successful an ISDD that diverts and sequesters the first 1.5–2 mL of blood would be in reducing blood culture contamination.
Following normal skin disinfectant protocols, phlebotomists drew two 20 mL blood samples, one via standard procedures and one generally drawn from the opposite arm using ISDD.
In addition to improving blood culture contamination rates, ISDD had similar sensitivity as standard phlebotomy in detecting true septicemia. The mean time to pathogen detection did not differ significantly between the two methods. The ratio of true-positive to false-positive culture for ISDD was 33:1 versus 4.3:1 for standard procedure.
A survey of phlebotomists involved in the study revealed that they were generally satisfied using ISDD.