title: Screening biological stains with qPCR versus lateral flow immunochromatographic test strips: a quantitative comparison using analytical figures of merit.
abstract: Biological fluid identification is an important facet of evidence examination in forensic laboratories worldwide. While identifying bodily fluids may provide insight into which downstream DNA methods to employ, these screening techniques consume a vital portion of the available evidence, are usually qualitative, and rely on visual interpretation. In contrast, qPCR yields information regarding the amount and proportion of amplifiable genetic material. In this study, dilution series of either semen or male saliva were prepared in either buffer or female blood. The samples were subjected to both lateral flow immunochromatographic test strips and qPCR analysis. Analytical figures of merit-including sensitivity, minimum distinguishable signal (MDS) and limit of detection (LOD)-were calculated and compared between methods. By applying the theory of the propagation of random errors, LODs were determined to be 0.05 μL of saliva for the RSID™ Saliva cards, 0.03 μL of saliva for Quantifiler(®) Duo, and 0.001 μL of semen for Quantifiler(®) Duo. In conclusion, quantitative PCR was deemed a viable and effective screening method for subsequent DNA profiling due to its stability in different matrices, sensitivity, and low limits of detection.
authors.affiliation: DNA Unit, Forensic & Technology Center, Massachusetts State Police, 124 Acton St., Maynard, MA, 01754; Biomedical Forensic Sciences, Boston University School of Medicine, 72 E. Concord St., Rm R806, Boston, MA, 02118.
authors.forename: Crystal Simson
authors.initials: CS
authors.lastname: Oechsle
authors.forename: Sandra
authors.initials: S
authors.lastname: Haddad
authors.forename: Joanne B
authors.initials: JB
authors.lastname: Sgueglia
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Grgicak
mesh_terms: D001774:Blood Chemical Analysis; D002846:Chromatography, Affinity / Q000295:instrumentation*; D016172:DNA Fingerprinting / Q000379:methods*; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008297:Male; D008853:Microscopy; D060888:Real-Time Polymerase Chain Reaction; D012463:Saliva / Q000737:chemistry; D012661:Semen / Q000737:chemistry / Q000166:cytology; D029607:Seminal Vesicle Secretory Proteins / Q000032:analysis; D013094:Spermatozoa / Q000166:cytology; D000516:alpha-Amylases / Q000032:analysis
chemical_list: D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D000516:alpha-Amylases
keywords: DNA quantification; biological screening; forensic DNA analysis; forensic sciences; limit of detection; real-time polymerase chain reaction