An international external quality assessment for molecular diagnosis of hereditary recurrent fevers: a 3-year scheme demonstrates the need for improvement.

Hereditary recurrent fevers (HRF) are rare diseases caused by molecular defects in genes involved in the regulation of innate immunity. Sixty-seven international laboratories participated in an external quality assessment (EQA) scheme, which was developed to appraise the accuracy of genetic testing. Reports were evaluated for the 12 items recommended by the OECD (Organisation for Economic Co-Operation and Development) guidelines for molecular diagnostics. The best documented items were the name of the gene, the biologist, or the patient, whereas information on the test and screening limits, and clinical interpretation of the disease inheritance were scarcely provided. The mutation nomenclature was incomplete in about 70% of the cases. In the first 2 years of EQA, we identified almost 30% genotyping error rate, which decreased markedly in the last year. The combined performance on the basis of the correct identification of all genotypes by a given laboratory in all the 3 years was only 40%, showing a critical need for improvement.