Characteristics and performance of the external quality assessment scheme (EQAS) for haematology in Spain. Ten years of experience.

: The external quality assessment scheme for haematology (EQAS-H) in Spain started in 1984 with 56 laboratories, being 473 in 1994. Participants come from public health services (70%) and from private laboratories (30%). Surveys are performed monthly or quarterly depending on the tests and on each occasion the following samples are prepared and sent by the professional organizing team: human (HIV/HBsAg free) or equine whole blood for cell counts (erythrocytes and leucocyte), platelet suspensions for platelet counts, lyophilized plasmas for prothrombin time (PT), partial thromboplastin time (APTT), fibrinogen (F) and antithrombin III (ATIII), and blood films for cell morphology and reticulocyte counts. In 1992 a new scheme on oral anticoagulant treatment control (OATC) has been established jointly by the Spanish Haematology Association (AEHH) and the Spanish Society of Thrombosis and Haemostasis (SETH). After preparation, the control material is sent to participants in the scheme where the requested tests are performed and the results reported back to the organizer (Haematology Laboratory Department of Hospital Clinic i Provincial) for statistical analysis. For evaluating the results, laboratories are divided into four to eight groups depending on the methodologies used. Individual results are assessed against a consensus value (mean) and a deviation index (DI) from the mean, and the coefficient of variation (CV), Youden plots and other statistical information are provided for all results and groups of each parameter. More than 80% of laboratories responded regularly (up to 6 trials) for blood counts and haemoglobin and compared to the previous year (1984), the values of CV(%) improved significantly for RBC count (from 3.3 to 2.2%), haemoglobin (from 2.7 to 2.1%) and platelet count (from 22.6 to 16.3%).(ABSTRACT TRUNCATED AT 250 WORDS)