402 INITIAL PLATELET CONCENTRATE CULTURE Margaret Cunningham

In a series of important studies Murphy and his colleagues demonstrated that the preparation and storage of platelet-rich plasma and platelet concentrates at 22°C rather than 4°C improved their life span in vivo (Murphy and Gardner, 1969; Murphy, Sayar, and Gardner, 1970). The potential clinical relevance of this finding has been confirmed by Handin and Valeri (1971), and it is likely that this approach to platelet procurement and storage will be widely instituted. Although Murphy and Gardner (1969) drew attention to the possible danger of bacterial proliferation if a storage temperature of 22°C was introduced, they concluded that in practice it was likely to be minimal. This conclusion has been supported by the findings of Silver, Sonnenwirth, and Beisser (1970) and of Katz and Tilton (1970) who found no evidence of bacterial contamination in 140 platelet concentrates stored at room temperature for up to 96 hours. Other studies by Buchholtz, Young, Friedman, Reilly, and Mardiney (1971) indicated an estimated minimal contamination rate of 24% in individual platelet concentrates stored at room temperature. However, the magnitude of bacterial contamination was not recorded as quantitative techniques were not used, but it was assumed to be low as the overall frequency of clinically significant infections or reactions appeared to be quite small. In view of the significant discrepancies between these three studies, the clinical importance of the administration of contaminated blood products to a large proportion of patients who are likely to be immunosuppressed, and the knowledge that certain bacteria cause aggregation of platelets (Clawson and White, 1971), a study of the bacterial contamination of platelet concentrates prepared and stored at room