Presumptive test

A fast, low-cost, class-specific screen used to triage a caseload before instrumental work begins. Examples are Marquis reagent for opioids and amphetamines, Trinder for salicylates, the Reinsch test for heavy metals, and immunoassay strips for opiates and cannabinoids in urine. A presumptive positive never names a molecule on its own in an Indian FSL report.