C. Ricos et al., EXTERNAL QUALITY ASSESSMENT - CURRENTLY USED CRITERIA FOR EVALUATING PERFORMANCE IN EUROPEAN COUNTRIES, AND CRITERIA FOR FUTURE HARMONIZATION, European journal of clinical chemistry and clinical biochemistry, 34(2), 1996, pp. 159-165
A questionnaire was circulated to European countries seeking informati
on on the criteria used for acceptable performance in external quality
assessment schemes. Responses were obtained from 21 countries. Fixed
limits are used in 13 countries but the basis for these varies widely
and includes clinical decision making, biological variation, views of
experts, the state-of-the-art, and combinations of approaches. Variabl
e limits based upon statistical analysis of the performance attained a
re used in 8 countries. The many advantages of harmonization in Europe
have prompted the development of criteria based upon within- and betw
een-subject biological variation for use in schemes which circulate si
ngle specimen challenges. Currently used criteria, which show much div
ersity, are compared with these proposals, and the empirical nature of
the majority of the former is demonstrated.