Method Evaluation of the QuidelOrtho Diagnostics Vitros NT-proBNP II Assay

Figures

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  Figure 1. The claimed analytical measurement range of 20–30,000 pg/mL was verified on two Vitros 5600 Integrated Systems, Vitros A (A) and Vitros B (B).

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  Figure 2. Results from method comparison studies analyzed with Passing–Bablok regression and Bland–Altman plots. Positive proportional biases were observed when comparing results from the Vitros NT-proBNP II assay using the Vitros A and B analyzers with results from the Vitros NT-proBNP assay (A–D). Results from both Vitros 5600 Integrated Systems were comparable (E,F). In the Passing–Bablok plots, regression lines are plotted in red. In the Bland–Altman plots, the mean average is represented by the blue solid line, and the 95% Limits of Agreement (LoA) is represented by the blue dashed lines. In both the Passing–Bablok plots and the Bland–Altman plots, the identify line indicating no differences between the test and reference methods is plotted in grey.

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  Figure 3. Results from the specimen-type comparison study analyzed with Passing–Bablok regression (A) and Bland–Altman plot (B). In the Passing–Bablok plots, regression lines are plotted in red. In the Bland–Altman plots, the mean average is represented by the blue solid line, and the 95% Limits of Agreement (LoA) is represented by the blue dashed lines. In both the Passing–Bablok plots and the Bland–Altman plots, the identify line indicating no differences between the test and reference methods is plotted in grey.

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  Figure 4. Results from QuidelOrtho’s method comparison study between both the Vitros NT-proBNP and NT-proBNP II assays. With unweighted Deming regression analysis performed by the vendor (A), no proportional bias was found. However, a closer analysis of the Bland–Altman plot (B) showed that the statistical analysis was skewed by the two very elevated results exceeding 13,000 pg/mL. In the Passing–Bablok plots, regression lines are plotted in red. In the Bland–Altman plots, the mean average is represented by the blue solid line, and the 95% Limits of Agreement (LoA) is represented by the blue dashed lines. In both the Passing–Bablok plots and the Bland–Altman plots, the identify line indicating no differences between the test and reference methods is plotted in grey.