Laboratory diagnosis of the rare anaemias: external quality assessment benefits patient care

Abstract

Since its introduction in the 1960s, external quality assessment has developed to become an essential component of the quality management system of the diagnostic laboratory. External quality assessment provides a long term, retrospective view of laboratory performance, demonstrating the competence of the laboratory to others. The ENERCA project (the European Network for Rare and Congenital Anaemias) has established a list of core laboratory tests that are used in the diagnosis of rare and congenital anaemias, which has been used as the basis for questionnaires to laboratories, to establish the use and quality assurance of diagnostic testing in the congenital and rare anaemias, and to European EQA providers for services in this key area. In general, the provision of EQA for rare and congenital anaemias is widely variable with little provision for the very rare disorders. For the more common congenital anaemias, such as the haemoglobinopathies and thalassaemias, provision is better but there is variation in aspects of the scheme design, especially the frequency of distribution. Where laboratories did not take part in EQA for individual tests, or there was no EQA available, a desire to participate was expressed in 66% (102/154) of cases. The provision of external quality assessment (EQA) services for rare disorders is a challenge. For many of these conditions, the number of patients in any one member state is very small with only a few laboratories providing diagnostic testing. In these cases, the development of pan-European or cross-border EQA may be the only means by which standardisation of methods and results can be achieved. An EQA survey of 243 laboratories for performance in Hb A2 quantification showed encouraging results in that there was a clear differentiation in the results from a beta Thalassaemia carrier and an individual with no evidence of Thalassaemia; however, a bias was observed between different methods of measurement.