External quality survey results of newborn deafness gene mutations in China

Objective To evaluate the external quality survey results of newborn hereditary deafness gene mutations to improve and enhance the testing quality of hereditary deafness gene mutations. Methods Each of 30 voluntarily participating laboratories testing newborn hereditary deafness gene mutations received 15 lots of quality control blood spots in this survey at May 2013, including mitochondria DNA 12SrRNA 1555A>G (201311-201315), SLC26A4 IVS7-2A>G (201321-201325) and GJB2 235delC (201331-201335). The testing results, methods, equipments and reagent information were submitted for analyses of Clinet EQA, Microsoft Excel 2007 and SPSS 13.0. The rates of correction (number of correct results/total number of submitted results) were used for evaluating the performance of laboratories. Results Among them, 24 laboratories submitted the testing results of mitochondria DNA 12SrRNA 1555A>G and the rate of submission was 80.0% (24/30). The rates of correction for each lot were 95.8% (23/24), 95.8% (23/24), 100% (24/24), 95.8% (23/24) and 95.8% (23/24) respectively and the overall rate was 96.7% (116/120). And 23 laboratories submitted the other two kinds of genetic test results, the rate of submission was 76.7% (23/30); the rates of correction for each lot of SLC26A4 IVS7-2A>G genetic test were 95.7% (22/23), 95.7% (22/23), 100% (23/23), 95.7% (22/23) and 95.7% (22/23) respectively and the overall rate was 96.5% (111/115); the genetic test results of GJB2 235delC were all correct (23/23). In this survey, 2/3 laboratories employed fluorescent polymerase chain reaction (PCR) and the remainder microarray chips. Conclusions The survey of newborn deafness gene mutation testing results is generally satisfactory. Only mitochondria DNA 12SrRNA and SLC26A4 have some errors. The laboratories of gene testing should improve their quality control system, correct mistakes during the test period without any delay and boost the rate of correction for newborn hereditary deafness gene testing. Key words: Neonatal screening; Hearing loss; Quality control; Mitochondria DNA 12SrRNA; SLC26A4; GJB2