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) (17) Gas Chromatography/Mass Spectrometry (GC/MS) (5) Headspace Gas Chromatography (GC) (13) (-) High Performance Liquid Chromatography/ Tandem Mass Spectrometry (LC-MS/MS) (2) High Performance Liquid Chromatography/Time of Flight-Mass Spectrometry (LC/TOF-MS) (14) Sample Type (-) Blood (1) (-) Serum or Plasma (1) Umbilical Cord (1) Urine (1) Test Area Therapeutics (2) Test Category Analgesics (2) Test Sub-Category Opiates/Opioids (2) Test Test Name 4312B Tapentadol - Free, Blood 4312SP Tapentadol - Free, Serum/Plasma