Clinical and Laboratory Standards Institute guideline C63 -Laboratory Support for Pain Management Programsprovides recommendations for medical laboratory toxicology-based testing services in support of the care and treatment of persons in pain management programs. This guideline discusses specimen types and collection, testing methodologies, and results reporting and interpretation. The intended users of this guideline include medical laboratory scientists and personnel, medical technologists, hospital administrators, physician office personnel, risk managers, pharmacists, and health care providers tasked with implementing pain management testing for their institutions or networks.