Comparison of lysis-centrifugation with lysis-filtration and a conventional unvented bottle for blood cultures.

Evaluation of a commercially available lysis-centrifugation blood culture system (Isolator, DuPont Co., Wilmington, Del.) and a lysis-filtration blood culture system for 3,111 cultures showed that both methods had comparable recoveries (73 and 68%, respectively) of significant aerobic and facultatively anaerobic isolates. The unvented conventional blood culture bottle had a recovery rate of 59%. Although the lysis-centrifugation and lysis-filtration systems had comparable recoveries of pathogens, the lysis-centrifugation system had the advantage of having colonies immediately available for further testing. The contamination rate with the lysis-centrifugation system was 3%, compared with 6% with the lysis-filtration system and 0.4% with brain heart infusion.