Blood residues on stone tools: Indoor and outdoor experiments

Three series of bloodstained flakes and bones were buried in soil out of doors, retrieved month by month, and tested using a sensitive and specific ELISA with monoclonal antibodies to see if any human albumin or IgG, or bovine albumin, could be detected. A few tests were positive, including a scraper examined after twelve months’ burial, but many were negative. A fourth series of bloodstained flakes kept in laboratory conditions tested highly positive for albumin and IgG after two years. The results are compared with other experimental work and with published identifications of blood from ancient sites, and factors which might have a significant effect on antigen survival are discussed.