Drug screening is a process used to identify and detect the presence of drugs or their metabolites in a biological sample, such as urine, blood, or saliva. It is commonly used in various settings, including workplaces, sports organizations, and healthcare facilities, to ensure compliance with drug policies and regulations. Drug screening tests can help determine if an individual has been using illegal substances or prescription medications, and can also be used to monitor medication adherence or detect drug abuse. Techniques used in drug screening include immunoassays, chromatography, and mass spectrometry.