The two luminol preparations used in the study were designated Luminol one and two on the basis of concentration. Luminol one, the more concentrated, was prepared according to Gordsky et al. and contained sodium perborate, luminol, and sodium carbonate in distilled water. Luminol two, prepared according to Wever, included sodium hydroxide, hydrogen peroxide, luminol and distilled water. Neither luminol preparation had any noticeable effects on the presumptive blood test, Takayama confirmatory test, specific identification of blood stains, or ABO typing. However, both luminol preparations affected certain genetic markers, most notably the Group IV system of electrophoresis. The migration pattern of hemoglobin was severely distorted by both preparations and phenotyping was not possible. Luminol one destroyed the activity of peptidase A (PEPA), and luminol two decreased the intensity of the PEPA bands to the point that they were not typable. The activity of carbonic anhydrase II (CAII) was also diminished by both luminol preparations to the point that phenotyping was not possible. Generally, luminol two had the least deleterious effects because it was the less concentrated preparation. 3 figures, 2 tables, and 27 references (Author abstract modified)