Precision of progesterone measurements with the use of automated immunoassay analyzers and the impact on clinical decisions for in vitro fertilization  Phillip E. Patton, M.D., Jeong Y. Lim, Ph.D., Lee R. Hickok, M.D., L. Michael Kettel, M.D., Janine M. Larson, B.S., M.Ed., K.Y. Francis Pau, Ph.D.  Fertility and Sterility  Volume 101, Issue 6, Pages 1629-1636 (June 2014) DOI: 10.1016/j.fertnstert.2014.02.037 Copyright © 2014 American Society for Reproductive Medicine Terms and Conditions

Figure 1 Comparison of P measurements by direct immunoassay and liquid chromatography–tandem mass spectrometry (LC-MS/MS) with the use of Deming regression. The solid line indicates the Deming regression line, and the dashed line indicates y = x. The slopes of the regression line between LC-MS/MS and the Immulite, Tosoh, Access II, and Roche Cobas analyzers, respectively, were 0.86, 0.75, 0.82, and 0.79 and the intercepts 0.45, 0.19, 0.42, and 0.18. The coefficient of correlations (R values) were 0.993, 0.995, 0.995, and 0.987 between LC-MS/MS and the Immulite, Tosoh, Access II, and Roche Cobas analyzers, respectively. Fertility and Sterility 2014 101, 1629-1636DOI: (10.1016/j.fertnstert.2014.02.037) Copyright © 2014 American Society for Reproductive Medicine Terms and Conditions