The collaborative study on typing group-specific component in casework bloodstains

Casework bloodstains were typed for group-specific component (GC) at eight forensic laboratories. Approximately 600 bloodstains were examined of which a mean of 62.7% gave results. This is comparable to other blood grouping systems in current use. Stains that were over three-months old were successfully typed in six of the laboratories. A wide variety of substrates was examined; these included many items of clothing as well as metal blades, concrete, paint, cement, glass and grass. Of substrates that were examined several times, none consistently gave problems with GC typing. The GC system has been shown, therefore, to be an effective test in operational forensic science.