Many diseases or applications of drugs significantly alter the chemical composition of body fluids, such as changing metabolic levels or adding xenobiotics and their metabolites. Clinical chemistry is the study of chemical and biochemical mechanisms of the body in relation to disease, mostly through the analysis of body fluids such as blood or urine.
Clinical chemists use a wide range of techniques to detect these changes. Typically, automated assays are used for standard tests that occur in higher frequency. These tests tend to be based on monitoring of target drugs or metabolites by immunoassays or liquid chromatography coupled with mass spectrometry (LC-MS).