Bacterial contamination: effect and limit of initial flow diversion

Abstract

Bacterial contamination of blood components is the major residual risk in modern transfusion medicine. To cope with this risk that often leads to a serious clinical outcome in transfused patients, various strategies have been devised and implemented in each step from blood drawing process at donation site to bedside practice of transfusion. Initial flow diversion is such strategy and was first introduced following the observation of the marked difference in the bacterial contamination level between the sample from the initial flow immediately after venepuncture and the samples successively collected after the diversion of several tubes of blood for testing [1]. It was expected that the diversion of the initial flow that might contain the largest amount of bacteria derived from the puncture site of the blood donor’s skin would lower the contamination level in the subsequent blood flow. The effect of this relatively simple method was first evaluated in an in vitro experimental system and then confirmed in a small-scale blood collection setting. Today, most blood collection facilities in developed coun- tries have implemented this technique in the blood draw- ing process and the effect of this method on the decrease in the frequency of bacterial contamination has been evaluated in real blood collection settings [2–5]. In this article, we describe the implementation of initial flow diversion in Japanese Red Cross blood centers, the result of the evaluation of its effect and its limitation as a measure to prevent bacterial contamination in blood com- ponents.