Diversion of first blood volume results in a reduction of bacterial contamination for whole-blood collections

Background and Objectives In a previous study we established a reliable setpoint for the prevalence of bacteria in whole blood. In the present study we investigated the possible preventive effect, of diversion of the first 10 ml of a blood donation, on the bacterial contamination rate. Materials and Methods To divert the first 10 ml of a whole-blood donation, we used a special five-bag system equipped with a Composampler(R) device. After venepuncture, the first 10 ml of a donation was sampled into a vacutainer tube. This was followed by the collection of the whole-blood unit. The extra bag allowed direct sampling of the final donation in a closed system for BacT/Alert. Whole-blood samples were taken after storage (2-14 h at 20 degreesC) and subsequent mixing. BacT/Alert culture bottles were incubated until positive, or for 7 days if negative. Confirmation and identification of positive cultures was performed according to internationally recognized standard reference methods. Results The prevalence of bacteria in whole blood, as determined by using standard collection techniques, was 0.35% (95% confidence interval 0.27-0.44%, n = 18 257). After diversion of the first 10 ml this value was significantly lower: 0.21% (P < 0.05, 95% confidence interval 0.12-0.35%, n = 7087). Most strikingly, a reduction in the frequency of staphylococcal species was observed (P < 0.02, reduction from 0.14 to 0.03%). Conclusions Diversion of the first 10 ml of blood was shown to contribute significantly to a reduction in the prevalence of superficial skin bacteria in whole-blood units. In our opinion, blood collection systems should be adapted to use the first 10-30 ml of a whole-blood donation for testing purposes.