SVT™ S-U-DS™ (Surfactant) Reagent U.S. Patents and Patents Pending. Usage: This assay is not for use in diagnosing disease or illness to effect treatment, and/or cure; it is For Forensic / Toxicology use to detect the presence of surfactant(s) in urine submitted for drugs of abuse testing. Method: Colorimetric : Endpoint. Principle: Surfactants, if...