Comparative studies between counterimmunoelectrophoresis and microprecipitation method of identification of human minute bloodstains.

A minute bloodstain on a thread 2 mm in length was tested to identify human origin by counterimmunoelectrophoresis (CIE), modified CIE, and microprecipitation method (MPM), using anti-human HbA serum. The detection limits expressed as the highest dilution of human blood on the thread in positive reaction were 1:160, 1:320, and 1:320 in CIE, modified CIE, and MPM, respectively. About 1 h was required to obtain the results. In CIE and modified CIE, the detection limits diminished according to the reduction of the samples from one half to one-eighth of the thread, but not in MPM.