With more than 18,100 members, the College of American Pathologists (CAP), headquartered in Northfield, Illinois, is the world’s largest association composed exclusively of board-certified pathologists certified by the American Board of Pathology, the Royal College of Physicians and Surgeons of Canada, the American Osteopathic Board of Pathology, or other certifying body approved by the CAP Board of Governors, and pathologists-in-training. It is widely considered the leader in laboratory quality assurance and advocates for high-quality and cost-effective medical care. The CAP inspects and accredits medical laboratories under deemed authority of the Centers for Medicare & Medicaid Services (CMS). Currently, the CAP accredits more than 7,600 laboratories globally, including mostly hospital laboratories as well as commercial laboratories and contract research organizations. The CAP Laboratory Accreditation Program’s goal is to improve patient safety by advancing the quality of pathology and laboratory services through education, standard setting, and ensuring laboratories meet or exceed regulatory requirements. The program incorporates stringent requirements while also providing laboratories the road map and tools to achieve these requirements. The CAP also offers specific accreditation programs for Forensic Drug Testing, Reproductive Laboratories, Biorepositories, and ISO 15189. In addition, more than 20,000 laboratories are enrolled in the CAP’s Proficiency Testing/External Quality Assurance (EQA) or “Surveys” program. With more than 600 Surveys, the CAP’s PT/EQA program is the largest laboratory peer-comparison program in the world. It allows laboratories to evaluate their performance regularly and improve the accuracy of the patient results they provide. Through these programs, the CAP provides individual laboratories with unknown specimens for testing. The participants analyze the specimens and return the results to the CAP for evaluation. Then, each participating laboratory receives a report of its performance as well as a report summarizing the results of all participating laboratories.