LABORATORY PERFORMANCE OF HEMOPHILIA CENTERS IN DEVELOPING-COUNTRIES - 3 YEARS EXPERIENCE OF THE WORLD-FEDERATION-OF-HEMOPHILIA EXTERNAL QUALITY ASSESSMENT SCHEME

A World Federation of Hemophilia External Quality Assessment Scheme ha s been established to promote high standards of laboratory performance in haemophilia centres worldwide. Results from 21 International Haemo philia Training Centres (IHTCs) provide target values for the prothrom bin time (PT), activated partial thromboplastin time (APTT), factor VI II:C, IX:C and von Willebrand factor (VWF) assays, against which the p erformance of Haemophilia Centres in developing countries (HCs) can be assessed. Eight surveys were distributed over a 3-year period between 1994 and 1997. A higher proportion of HCs failed to identify an abnor mal PT or APTT in samples from donors with mild deficiencies of the ex trinsic and intrinsic systems, respectively. For factor VIII:C and IX: C assays, agreement between HC results was consistently poorer than be tween IHTCs. However, improvement in between-centre agreement could be seen for two samples distributed on more than one occasion. A minorit y of HCs perform assays for VWF, and a questionnaire revealed equipmen t and reagent costs as limiting the range of assays which could be car ried out in several centres. However, agreement was in some cases bett er between those HCs that did perform VWF assays than between IHTCs. T he problems of screening test sensitivity and between-centre agreement for factor assays need to be addressed, together with the limitations which prevent HCs from performing a full range of tests in the diagno sis and treatment of bleeding disorders.