Assessment of the Leeds Spectral Vision System for Detecting Biological Stains on Fabrics

This study is a comparison of the performance of the Leeds Spectral Vision system (infrared and 455 nm) with the Polilight-Flare((R)) Plus UV (365 nm) and the Mini-CrimeScope 400 CSS (485 nm) filter for detecting biological stains (blood, semen, saliva and urine) on a variety of fabric substrates. The samples included neat and diluted stains (1/2, 1/10, 1/50 and 1/100), layered stains and stains prepared using different volumes of fluids (20, 10 and 3 mL) to observe the sensitivity of different filters. The detection of blood in the presence of stains created by household materials that appear visibly similar to blood under ambient lighting was also assessed. The detection of biological stains from blood, semen and urine (10 mL) and saliva (100 mL) were also assessed on three brands of diapers. The blue filter was the optimal choice for the detection of bodily fluids that fluoresce (semen, saliva and urine), performing equally or better than the ultraviolet and outperforming the infrared. The infrared was more effective at detecting blood on all fabric types except white cotton and when blood was mixed with other bodily fluids. The infrared showed improved specificity to blood compared with the CSS filter when stains from fluids other than blood were present.