Under the Omnibus Budget Reconciliation Act of 1986, the United States Congress has called for a study of the quality of care of Medicare beneficiaries and a strategy to assure it. The quality of laboratory services is an important component of that assessment and assurance, and hospitals need a methodology for it. The Guidelines for Quality Assessment of the Council on Medical Service of the American Medical Association can be used as a basis for a model that links structure, process, and outcome criteria to the interplay of people, equipment, and systems that comprise the laboratory. This can then support the development of a monitoring and evaluation program for its services.