Detection of penicillins in the sera of 'healthy' blood donors.

10,853 sera, collected from 'healthy' blood donors during the period December 1977 to May 1979, were tested for the presence of penicillinase-sensitive penicillins by a bioassay technique using Bacillus subtilis ATCC 6633 as test organism. Their presence could be demonstrated in 30 sera (0.27%), at concentrations equivalent to 0.2--4.0 micrograms/ml of penicillin G. The implications of these findings are discussed, particularly the possibility of their relationship to nonhemolytic adverse reactions to transfusion.