Bland-Altman analysis.

<p>Bland-Altman plots of <b>(A)</b> CD4 T-cells < 200/mm³, <b>(B)</b> between 200 and 350/mm³, <b>(C)</b> between 350 and 500/mm³, and <b>(D)</b> above 500/mm³ according the CD4 cell count levels. For each plot, the x-axis represents the average of CD4 count between the PIMA and the BD FACSCount^TM, and the y-axis represents the bias (difference) between the PIMA^TM Alere and the BD FACSCount^TM. The solid red line represents the mean of the difference between the two measurements, and the light black lines represent the upper and lower limits of agreement (ULA: mean differences plus and 1,96 x standard deviation of the mean difference; LLA: mean differences minus and 1,96 x standard deviation of the mean difference)