Laboratory Corporation of America Holdings is a clinical laboratory company. Through a network of laboratories, the Company offers a range of clinical laboratory tests that are used by the medical profession in core testing and patient diagnosis, and in the monitoring and treatment of disease. The Company has also developed testing operations, such as oncology testing, HIV genotyping and phenotyping, diagnostic genetics, cardiovascular disease risk assessment, HCV diagnosis and monitoring, and clinical trials. The Company has a national network of 44 primary laboratories and 1,700 patient service centers (PSCs) along with a network of branches and STAT laboratories (which are laboratories that have the ability to perform certain core tests and report the results to the physician quickly). Its clients include physicians, hospitals, managed care organizations, governmental agencies, employers, pharmaceutical companies and other independent clinical laboratories.