PROFICIENCY TESTING IN LABORATORY MEDICINE - USES AND LIMITATIONS

Objective. - To provide a critical review of recently published litera ture on the effectiveness, uses, and limitations of proficiency testin g (PT) as a mechanism for laboratory improvement, and to explore ways to improve the PT process. Data Source. - All publications identified by a MEDLINE search of the literature dating back to 1987 on the subje ct of ''proficiency testing'' in laboratory medicine, as well as selec ted references cited in recent review articles. Study Selection. - No specific selection criteria were used for inclusion of publications id entified by the MEDLINE database as long as they dealt with PT as a me chanism of medical laboratory improvement or a measure of laboratory p erformance. Data Extraction. - Abstractions of data were made dependin g on relevance of the data. Data Synthesis. - Proficiency testing data are an indicator, but not a measure, of laboratory performance. Limit ations of current PT practices are incomplete assessment of the total testing process, PT materials being treated differently than those fro m patients, PT performance criteria, and ''matrix effect.'' Proficienc y testing performance has been related to length of PT experience, tes t environment and volume, institutional size, laboratory and analyst w orkload, difficulty of PT materials, performing quality control, testi ng methodology, and degree of automation. Conclusions. - Proficiency t esting has a well-established role as both a laboratory improvement an d an educational tool. There are, however, several practical and desig n limitations even for the best-administered PT programs. Suggestions to improve the PT process include increased reliance on PT results in combination with other quality indicators (such as performance in regi onal surveys), occasional use of ''blind'' PT, introduction of biologi cal materials to PT participants, electronic grading and reporting of PT results, and introduction of challenging PT materials to fulfill th e educational role of PT.