The impact of heat and UV radiation on forensic immunoassay test kits for blood

Presently, unexplained false negatives for the confirmatory immunoassay for human blood, ABACard� HemaTrace� (HemaTrace), have been observed in casework at Victoria Police, where a what appears to be bloodstain tests positive for the presumptive test HemaStix and yields a full DNA profile but cannot be confirmed as human blood due a negative HemaTrace result. Despite preliminary research indicating factors which degrade haemoglobin can impact the integrity of HemaTrace, there is a lack of published information regarding the impact of specific temperatures and/or UV radiation on whole blood samples. This research assessed the impact of temperature and UV radiation on the forensic immunoassay assay test kit, ABACard� HemaTrace�, whilst analysing the blood sample for DNA and chemical degradation. Storage temperatures of -???????? ???????????????? showed minimal to no degradation of blood samples with one month incubation and did not affect the testing outcomes of HemaStix (n=6) nor HemaTrace (n=18). The only time HemaStix false negatives were observed was in the case of burnt or charred blood for exposure periods of five to minutes using a Webber Barbeque (n=7). This study showed exposure oh high temperatures of ????????????for three to six-hours (n=6) and ?????????????????????????? to six hours (n=18) showed degradation in the blood and affected HemaTrace testing outcomes . Blood samples deposited onto the outside a stationary vehicle for one week with a maximum ?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? affected HemaTrace testing outcomes (n=12), whilst blood samples on the inside of the stationary vehicle showed lower levels of degradation and did not affect HemaTrace testing outcomes (n=24). UV-B radiation did not degrade whole blood samples after exposure periods up to one week (n=18) but did degrade naked DNA after 10 hours (n=2). Implicating current forensic laboratory sterilisation methods may be prone to contamination.