An investigation into the impact of infrared radiation, solar radiation and burial exposure on the efficacy of forensic immunoassay testing

Blood, semen, and saliva are found at crime scenes and are known to be the most common biological materials used as forensic evidence. Each of these bodily fluids has its own forensic immunoassay test designed to target the specific antigens within the biological sample, which react with the antibodies within these immunoassay tests. However, these forensic tests can be influenced by external factors such as sunlight and burial conditions. These influences can generate false negative results, questioning the effectiveness of these immunoassay tests. The use of a cotton substrate was used to replicate ?real-life? crime, and the use of blood, semen and saliva were used as they are the most common biological materials found at crime scenes. And the tests that were used are ABAcard� HemaTrace� for blood, ABAcard� p30 test for semen, and RSIDTM-saliva for saliva, these are also used in the in the Victorian Police forensic laboratories. The aim of this study was to determine if different environmental conditions such as burial exposure and solar radiation, as well as infrared radiation can degrade blood, semen, and saliva over time can affect the efficacy of immunoassay tests such as ABAcard� HemaTrace�, RSIDTM-saliva and ABAcard� p30 test, which are used in forensic laboratories such as the Victoria Police Forensic Services Department. This study found that semen and saliva under solar exposure generates false negative results at 48 hours for semen and 2 weeks for saliva. This study also found that semen and blood generated false negative results under burial conditions, at 3 weeks for semen and between 3 weeks and 5 weeks for blood. These finding indicate that burial conditions and sunlight have a degradative effect on the biological samples which ultimately impact theeffectiveness of these specific immunoassay tests. Chemical analysis of each biological material under each experimental condition was made using biomarker m/z 557.17 for blood, m/z 399.08 for semen and m/z 181.08 for saliva. These biomarkers, however, were not deemed suitable to determine any degradation in these samples.