Figure 2

Analytical sensitivity and specificity estimates for US laboratories participating in external proficiency testing for cystic fibrosis mutation detection from 2003 to 2013. (a) The analytical sensitivity estimates for detecting CFTR mutations. Three samples had estimates below 97% (labeled) and were excluded from the regression. A second-order polynomial (solid curve) was fitted to the remaining data, and it showed significantly improving rates from 2003 through 2008, reaching a plateau that continues through 2013 (sensitivity = 0.98704 + 0.003453 × distribution − 0.0001138 × distribution2, where “distribution” represents numbers from 1 [2003A] to 21). (b) The corresponding analytical specificity estimates. The linear regression (solid line) shows no significant changes over time.