Developmental Validation of RSID™‐Saliva: A Lateral Flow Immunochromatographic Strip Test for the Forensic Detection of Saliva

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Abstract
Abstract:  Current methods for forensic identification of saliva generally assay for the enzymatic activity of α‐amylase, an enzyme long associated with human saliva. Here, we describe the Rapid Stain IDentification (RSID™‐Saliva), a lateral flow immunochromatographic strip test that uses two antisalivary amylase monoclonal antibodies to detect the presence of salivary amylase, rather than the activity of the enzyme. We demonstrate that RSID™‐Saliva is accurate, reproducible, and highly sensitive for human saliva; RSID™‐Saliva detects less than 1 μL of saliva. The sensitivity of RSIDTM‐Saliva allows investigators to sample a fraction of a questioned stain while retaining the majority for DNA‐STR analysis. We demonstrate that RSID™‐Saliva identifies saliva from a variety of materials (e.g., cans, bottles, envelopes, and cigarette‐butts) and it does not cross‐react with blood, semen, urine, or vaginal fluid. RSID™‐Saliva is a useful forensic test for determining which evidentiary items contain saliva and thus may yield a DNA profile.