Twenty-years of experiences in external quality assurance in Korea.

The Korean External Quality Assurance Scheme (KEQAS) was set up by a voluntary organization, the Korean Society of Quality Control in Clinical Pathology (KSQC) in 1976. The KSQC was reorganized as the Korean Association of Quality Assurance for Clinical Laboratories (KAQACL) in 1991. The KAQACL is a government authorized organization. With the growing popularity of the KEQAS, its coverage has expanded to include ten disciplines, and the number of participants has grown to 470 clinical laboratories by the end of 1998. The ten programs are: clinical chemistry, clinical microbiology, diagnostic hematology, diagnostic immunology. blood bank, urinalysis, immunoassay, TDM (therapeutic drug monitoring), inborn errors of metabolism and diagnostic genetics. KAQACL membership accreditation is based on the QAP return rate, of which the minimum criterion for acceptability is 50%. Membership in KAQACL is highly regarded by the Inspection and Accreditation Program of the Korean Hospital Association and is an essential requirement for outreach services of commercial laboratories. While monitoring the quality of laboratory performances during the last two decades, the KEQAS has provided information on reliability of laboratory performances regarding methods, manufacturers and laboratory groups. The inter-laboratory coefficient variations (CVs) and the variance index score (VIS) have gradually decreased over the years, particularly during the 1990s. The participants who achieved good performances (less than 100 VIS) in clinical chemistry tests have gradually increased in number up to 83.2% of all participants.