Comparison of Four Saliva Detection Methods to Identify Expectorated Blood Spatter

Blood spatter analysis is an important step for crime scene reconstruction. The presence of saliva in blood spatter could indicate expectorated blood which is difficult to distinguish from impact spatter. In this study, four saliva test methods (SALIgAE^®, Phadebas^® sheet, RSID^™-Saliva kit, and starch gel diffusion) were compared to identify the best method for detecting expectorated blood spatter. The RSID^™-Saliva kit showed the highest sensitivity even when saliva was mixed with blood, and was not inhibited by the presence of blood. The SALIgAE^® test provided easy and rapid results, but the yellow color of a positive reaction was overwhelmed by the red color of the blood. The starch gel diffusion method and the Phadebas^® sheet exhibited relatively low sensitivity and the assay took a long time. When using the RSID^™-Saliva kit for identifying saliva in blood, results should be read within 10min.