Biochemical markers, also known as biomarkers, are specific molecules or substances in the body that can be measured and indicate a biological or pathological process that is occurring. These markers are often used in research and clinical practice to diagnose diseases, track disease progression, and monitor the effectiveness of treatments. Biochemical markers can be found in various bodily fluids such as blood, urine, and saliva, and can include proteins, enzymes, hormones, antibodies, and genetic material. They provide valuable information about the biochemical and physiological status of an individual and can help healthcare professionals make informed decisions about patient care.