Test Catalog Search Home Test Catalog Search Testing Choices: From the standard to the extraordinary × Search Clear Filter by: Clear all Method(s) Enzyme-Linked Immunosorbent Assay (ELISA) (1) Gas Chromatography/Mass Spectrometry (GC/MS) (1) Headspace Gas Chromatography (GC) (1) (-) High Performance Liquid Chromatography/ Tandem Mass Spectrometry (LC-MS/MS) (1) Sample Type (-) Blood (1) Serum or Plasma (1) Urine (2) Test Area Test Category Test Sub-Category Test Test Name 4680B Trihexyphenidyl, Blood