External quality assessment in clinical chemistry: review of the situation in Croatia with particular reference to equipment.

The effect of the use of new flame photometers (Ciba Corning 480, Chiron, Salzburg, Austria) and multichannel analyzers (BM Hitachi 904 or BM Hitachi 911, both Boehringer GmbH, Mannheim, Germany) on analytical quality was assessed in a number of medical biochemical laboratories (n=58) at health centers and general hospitals that provide primary health care services for the respective catchment areas. The laboratories were supplied during 1996 and 1997 with new equipment, as part of the First Croatian Health Project, Primary Health Care Subproject, carried out by the Croatian Ministry of Health and Croatian Institute of Health Insurance. We evaluated analytical performance of these laboratories for 19 analytes, according to the results reported in the Croatian External Quality Assessment Program for medical biochemical laboratories, performed four times per year. Changes of percentages of particular methods used by the participating laboratories were observed for inorganic phosphate, total bilirubin, urea and creatinine. Such changes were even more pronounced for enzymes, where changes in the measurement procedure such as incubation temperature and buffers were observed in the methods used. Evaluation of method performance revealed that after the introduction of new equipment interlaboratory variation decreased, so that an increasing proportion of laboratories included in the Project produced results within the target limits.