Comprehensive Urine Drug Screen by Gas Chromatography-Mass Spectrometry (GC-MS).

Drug screening is an important diagnostic tool in patient management and is an indispensable part of clinical toxicology laboratory services. While some laboratories employ automated chemistry analyzers for limited screening of drugs of abuse and a few common over-the-counter drugs, more comprehensive and detailed drug screening is needed for better patient care. Comprehensive drug screening generally involves immunoassays, colorimetric tests, and gas or liquid chromatography-mass spectrometry. Mass spectrometry is widely regarded as the gold standard for comprehensive drug screening due to its ability to detect hundreds of drugs. In this chapter, we present an efficient and rapid gas chromatography-mass spectrometry (GC-MS) method for comprehensive drug screening of urine samples. This method involves a liquid-liquid sample extraction, sample concentration, and subsequent analysis using GC-MS.