Quality assurance programs in the United States.

The College of American Pathologists (CAP) provides quality assurance programs for clinical laboratories, including surveys for external quality assessment, quality assurance service for internal and regional quality control, and Q-probes for overall quality assurance including pre- and post-analytic factors. These are complemented by inspections through the laboratory accreditation program and a standards program linked with the national reference system for clinical chemistry. Expert resource committees, organized according to scientific disciplines, provide professional support and direction for these programs. Numerous other professional societies jointly sponsor various surveys, which optimize available expertise, size, and quality of these programs. CAP surveys are the most widely used programs for proficiency testing (PT) in the United States. PT programs only partially characterize performance. Clinical laboratories are best evaluated by a combination of measures, including EQA, internal and regional quality control, monitors of pre- and post-analytic quality, and inspection.