Several modifications have been made to a system of simultaneous phenotyping of EAP, EsD, PGM and ADA in bloodstains by isoelectric focusing, which improved the results of the system. An increase in the thickness of the gel improved the resolution of the isozymes' bands, especially PGM and EAP, and diminished the effect of overloading. By increasing the width of the gel it was possible to increase the number of samples applied to the gel. By coating one of the glass plates, used in the preparation of the gels, with a hydrophobic solution, separation of the plate from the gel was greatly facilitated. Finally, the system was found to be very useful as a rapid screening method prior to DNA testing.