A European pilot quality assessment scheme for molecular diagnosis of Huntington's disease.

This paper reports a European pilot External Quality Assessment (EQA) scheme for the molecular diagnosis of Huntington's disease (HD). The European Molecular Genetics Quality Network (EMQN) chose HD as a relatively simple assay that allows a range of difficulty in terms of technical competence and interpretation. Fourteen centres from 12 different countries participated. The scheme organiser provided five cases together with mock clinical information. The participating laboratories were asked to complete the analyses and return the reports in English to their normal laboratory format within a fixed period. The scheme demonstrates a level of potential misdiagnosis in molecular analysis of HD as well as a wide variety in way of reporting laboratory results. Overall 9/146 (6.2%) of alleles fell outside the set limits, and the rate of misdiagnosis was 1/78 (1.3%). A closer estimate of diagnostic accuracy will require expansion of the scheme.