Background: The Clinical Laboratory Improvement Amendments of 1988 (CLIA'88) mandate universal requirements for all U.S. clinical laboratory-testing sites. The intent of CLIA'88 is to ensure quality testing through a combination of minimum quality practices that incorporate total quality management concepts. These regulations do not contain established, objective indicators or measures to assess quality. However, there is an implicit assumption that compliance with traditionally accepted good laboratory practices--following manufacturers' directions, routinely analysing quality control materials, applying quality assurance principles, employing and assessing competent testing personnel, and participating in external quality assessment or proficiency testing (PT)--will result in improved test quality.
Methods: The CLIA'88 regulations do include PT performance standards, which intentionally or unintentionally, define intra-laboratory performance. Passing PT has become a prime motivation for improving laboratory performance; it can also be used as an objective indicator to assess whether compliance to CLIA has improved intra-laboratory quality.
Results: Data from 1994 through 2002 indicate that the percentage of laboratories passing PT has increased. In addition to PT performance, subjective indicators of improved quality--frequency of inspection deficiencies, the number of government sanctions for non-compliance, and customer satisfaction--were evaluated.
Conclusions: The results from these subjective indicators are more difficult to interpret but also seem to show improved quality in US clinical laboratories eleven years post-CLIA'88.