Drug test kits operate based on the principles of immunoassay, gas chromatography, and mass spectrometry. Immunoassay techniques are commonly used for initial screening due to their speed and cost-effectiveness. They work by using antibodies that bind to specific drugs or their metabolites. Positive results from immunoassays may need confirmation through more specific methods like gas chromatography-mass spectrometry (GC-MS), which provides a higher level of accuracy and specificity.
