Fig. 5
Passing-Bablock Regression Analysis Comparing Accre 8, Abbott, and Roche Analysis with LC-MS/MS for Vit B12 Measurements. Plots (A–C) illustrate the relationship between each assay and LC-MS/MS using Passing-Bablok regression analysis. Plot A presents the regression equation for Accre 8 vs. LC-MS/MS as y = − 58.763 + 1.444x (n = 239), indicating a proportional bias where Accre 8 overestimates Vit B12 at higher concentrations. Plot B compares Abbott vs. LC-MS/MS, yielding the equation y = − 21.818 + 0.934x (n = 239), showing a slight underestimation of Vit B12 by Abbott. Plot C illustrates Roche vs. LC-MS/MS, with the equation y = − 15.925 + 1.019x (n = 239), demonstrating the closest agreement with LC-MS/MS. Orange circles represent individual sample measurements, with LC-MS/MS values on the X-axis plotted against the corresponding Accre 8, Abbott, or Roche values on the Y-axis. The black solid line represents the Passing-Bablok regression fit, indicating the level of agreement between each method and LC-MS/MS. The red dashed line is the identity line (y = x), where perfect agreement would occur. The blue shaded region represents the 95% confidence interval (CI) for the regression line, with a wider spread at higher concentrations, suggesting increased variability and uncertainty in measurement agreement. The thin dashed lines surrounding the regression fit define the confidence limits for the slope.
