Results of the College of American Pathology/American College of Medical Genetics and Genomics external proficiency testing from 2006 to 2013 for three conditions prevalent in the Ashkenazi Jewish population.

[canavan disease]

The purpose of this study was to determine analytic performance of laboratories offering molecular testing for conditions such as Tay-Sachs disease , Canavan disease , and familial dysautonomia , which are prevalent in the Ashkenazi Jewish population .The College of American Pathologists and the American College of Medical Genetics and Genomics cosponsor molecular proficiency testing for these disorders . Responses from 2006 to 2013 were analyzed for accuracy (genotyping and interpretations ).Between 11 and 36 laboratories participated in each Tay-Sachs disease distribution . Samples tested per month were constant (2 ,900 ) from 2006 to 2011 but recently increased . Participants reporting <10 samples tested per month had longer turnaround times (42 vs . 7 %, longer than 14 days ; P = 0 .03 ). Analytic sensitivity and specificity for US participants were 97 .2 % (95 % confidence interval : 94 .7 -98 .7 %) and 99 .8 % (95 % confidence interval : 99 .1 -99 .9 %), respectively . Of 11 genotyping errors , 2 were due to sample mix-up . Analytic interpretations were correct in 99 .3 % of challenges (956 /963 ; 95 % confidence interval : 98 .5 -99 .7 %). Better performance was found for Canavan disease and familial dysautonomia . International laboratories performed equally well .These results demonstrated high analytic sensitivity and specificity along with excellent analytic interpretation performance , confirming the genetics community impression that laboratories provide accurate test results in both diagnostic and screening settings . Proficiency testing can identify potential laboratory issues and helps document overall laboratory performance .