Fig. 3.

Bland–Altman (mean-difference) plots showing repeatability of assays.

Dashed lines represent upper and lower 95% limits of agreement ($\mathbf{d}\pm \mathbf{1.96}\mathbf{s}$); dotted lines reflect the 95% confidence interval around the mean difference ($\mathbf{d}\pm {\mathbf{t}}_{\mathbf{c}\mathbf{r}\mathbf{i}\mathbf{t}}\times \mathbf{S}{\mathbf{E}}_{\mathbf{d}}$). Scatter represents the percentage difference between the first and second measurement plotted against their mean value. (A), Same aliquot, same analysis date; (B), different aliquot from the same lumber puncture, different analysis date.