The two primary methods used for hair analysis are immunoassay and chromatographic techniques. Immunoassays are often used for initial screening due to their ability to quickly process many samples. Confirmatory tests are usually done using chromatographic techniques like Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), which provide more specific and sensitive results.
