Organization and results of a pilot scheme for external quality assessment in clinical chemistry carried out in the Latium region, Italy.

The results of an external quality assessment scheme (EQAS), carried out in the Latium region between October 1987 and December 1988, are reported. Ninety-four laboratories, both public and private, took part in the scheme. Aim of the scheme was to estimate the reliability of the clinical chemistry services in this region. The participating laboratories received eight control samples for EQA, every two months. The analytes to be determined in each sample were: glucose (GLU), urea (UR), total protein (TP), uric acid (UA), creatinine (CR), bilirubin (BIL), cholesterol (CHO), triglycerides (TRI), sodium (Na), potassium (K), calcium (Ca), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CPK), gamma glutamyl transferase (GGT), and alkaline phosphatase (ALP). Global laboratory performances were evaluated in terms of interlaboratory precision, accuracy--as deviation per cent from the target values and coefficient of variation (CV)--and percentage of results within pre-set acceptability limits. The deviations were reasonably low, whereas the CVs were rather high. The percentage of acceptable results was lower than 50% for the analytes urea, calcium, uric acid, creatine kinase and alkaline phosphatase. The performance of the examined laboratories was worse than those obtained in other regional and national EQAS, both in terms of CVs and percentage of acceptable results.