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Validation of Highly-Specific Protein Markers for the Identification of Biological Stains

NCJ Number
Date Published
February 2013
54 pages
This study validated the specificity of the most promising candidate biomarkers for their target body fluids and the consistency of their proteins that are specific to a given body fluid compared to those that show inter-individual variability or which are present in non-target stains.
All core objectives of this research were achieved. Biomarker validation assays were conducted using a high-sensitivity mass spectrometry technology (Q-TOF). This enabled the detection of even low-abundance candidate biomarkers while avoiding the obstacles of alternative approaches that would be prohibitively expensive and time-consuming. There were clear and unambiguous identifications of the targeted high-specificity biomarkers for the following body fluids: seminal fluid, saliva, urine, vaginal fluid, and peripheral and menstrual blood. The inter-individual reproducibility of target ion detection was also found to be excellent across multiple samples. A total of 37 unique casework-type samples were assayed using the Q-TOF multiplex assay. The recovery of body fluid samples from a variety of substrates did not change the accuracy of the analysis of the fluid’s characteristics. Of the potential inhibitors assayed, only chewing tobacco juice apparently precluded the identification of a target body fluid. Fluids analyzed by the multiplex assay accurately identified both components in a single pass. Only in the case of saliva and peripheral blood did matrix effects impede the detection of salivary proteins. The information produced by this research will assist in facilitating the commercial production of such assays. This includes the development of a commercial mass spectrometry approach based on the multiplex assay described in this report. 11 figures, 2 tables, and 49 references
Date Published: February 1, 2013