title: Concordance study of 3 direct-to-consumer genetic-testing services.
abstract: BACKGROUND
  Several companies offer direct-to-consumer (DTC) genetic testing to evaluate ancestry and wellness. Massive-scale testing of thousands of single-nucleotide polymorphisms (SNPs) is not error free, and such errors could translate into misclassification of risk and produce a false sense of security or unnecessary anxiety in an individual. We evaluated 3 DTC services and a genomics service that are based on DNA microarray or solution genotyping with hydrolysis probes (TaqMan® analysis) and compared the test results obtained for the same individual.
  
  
  METHODS
  We evaluated the results from 3 DTC services (23andMe, deCODEme, Navigenics) and a genomics-analysis service (Expression Analysis).
  
  
  RESULTS
  The concordance rates between the services for SNP data were >99.6%; however, there were some marked differences in the relative disease risks assigned by the DTC services (e.g., for rheumatoid arthritis, the range of relative risk was 0.9-1.85). A possible reason for this difference is that different SNPs were used to calculate risk for the same disease. The reference population also had an influence on the relative disease risk.
  
  
  CONCLUSIONS
  Our study revealed excellent concordance between the results of SNP analyses obtained from different companies with different platforms, but we noted a disparity in the data for risk, owing to both differences in the SNPs used in the calculation and the reference population used. The larger issues of the utility of the information and the need for risk data that match the user's ethnicity remain, however.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Kenta
authors.initials: K
authors.lastname: Imai
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Kricka
authors.forename: Paolo
authors.initials: P
authors.lastname: Fortina
mesh_terms: D054626:Consumer Health Information; D004247:DNA / Q000235:genetics; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing / Q000191:economics / Q000379:methods / Q000592:standards; D006801:Humans; D008389:Marketing of Health Services; D020411:Oligonucleotide Array Sequence Analysis / Q000191:economics / Q000379:methods / Q000592:standards; D020641:Polymorphism, Single Nucleotide; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004247:DNA