A quantitative immunological study of plasma proteins in blood stains

An electroimmunodiffusion technique, which enables precise measurements of the concentrations of some plasma proteins in blood stain extracts to be made, has been developed. It is possible that if a number of plasma proteins, with high discriminating power were found to be stable in blood stains, and were measured by this technique, that the information so obtained could be of value for the forensic examination of blood stains. The tandem antigen–antibody crossed electrophoretic technique has also been examined, and its application to this problem assessed. Nine plasma proteins have been examined, and some of them found to be stable in blood stains. Additional immunological techniques l1ave been employed in an attempt to establish the nature of the changes which the unstable proteins underwent. Seven of the proteins were quantitated in samples provided in a number of blind trials, in order to test the feasibility of a plasma profiling system for matching blood stains. Finally, the advantages and disadvantages of a plasma profiling system over existing methods of blood stain analysis have been discussed.