Detection of blood on clothing laundered with sodium percarbonate

Laundering clothes with modern detergents containing sodium percarbonate can result in false negative results when certain presumptive and confirmatory tests are used to detect the presence of blood. This is problematic as blood evidence can be inadvertently overlooked and criminal activity concealed, simply by laundering bloodstained clothes in detergent. The aim of this research was to determine if the incidence of positive results using tetramethylbenzidine (TMB) reagent, luminol, Bluestar® Magnum, ABAcard® Hematrace® and RSID™-Blood was affected by treatment in hot and cold water, with and without the detergent, sodium percarbonate. This study identified that RSID-Blood consistently produced positive results irrespective of water temperature or the addition of sodium percarbonate. All other reagents returned positive results in the absence of sodium percarbonate, regardless of water temperature. The introduction of sodium percarbonate initiated negative results regardless of water temperature when testing with tetramethylbenzidine reagent, Bluestar® Magnum and ABAcard® Hematrace®. Luminol in the presence of sodium percarbonate responded differently to the temperature change of the water. Cold water returned positive results, however, hot water returned negative results. This research indicates that RSID™-Blood surpassed other blood screening tests identifying blood on sodium percarbonate treated cotton fabric. The results for luminol were varied depending on water temperature, however, luminol performed better as a presumptive test than TMB or Bluestar® Magnum.