Reducing blood culture contamination using an initial specimen diversion device

False positive blood cultures result from contamination, consuming laboratory resources and causing unnecessary antibiotic treatment and prolonged hospital stay. Skin disinfection reduces contamination; however, bacteria colonizing human skin are also found in tissues deep into the skin surface. A diversion device diverts the initial 1-2 mL of blood to remove any potentially contaminated skin plug. This study investigates the effect of the device on culture contamination in hospitalized patients.

In this prospective controlled pragmatic study, blood cultures were obtained using an initial specimen diversion device, either via integrated needle or attachment to a newly placed intravenous catheter. Cultures taken using standard methods served as the control.

Six hundred seventy-one blood cultures were obtained. Two hundred seven cultures were taken using an initial specimen diversion device, with 2 (1.0%) contaminated cultures. Four hundred sixty-four cultures were taken without the device, with 24 (5.2%) contaminated cultures (P < .008). No significant difference was shown in the rate of true-positive cultures.

The use of a diversion device was associated with reduced culture contamination in hospitalized patients over a 6-month period, without concomitant reduction in true-positive cultures. This intervention may result in a reduction in costs, antibiotic use, and duration of hospital stay.