Evaluation of bloodstain detection tests for forensic applications

Abstract

Recently the Bluestar Forensic Kit® a new luminol reagent based test was designed for blood detection. The aim of this study was to determine the followings parameters: time since collection; dilution and substrate. Samples of human and animal blood origin were tested according to those criteria. We verified that the Bluestar® Forensic Kit allows the detection of non-diluted and diluted bloodstains in different substrates. The maximum bloodstain dilution detected was 1/30 000 in denim jeans. False positive results due to the Bluestar® reaction with iron metallic particles present in everyday materials were frequent. The use of Bluestar® Forensic Kit on the samples does not interfere with DNA profile analysis. A non-diluted bloodstain was still detected although with less intensity, one month after reagent preparation. Two immunochromatographic tests (Rapid Stain Identification−RSID® and Hexagon OBTI) for confirmation of human blood were also compared. This study demonstrates that both are efficient but the Hexagon OBTI much quicker and essential to confirm the presence of human blood traces