Comparison of the CD4 counts obtained by PIMA analyzer and reference methods using venous blood from 1790 samples . Figure 1A: Linear regression analysis: The CD4 counts obtained by PIMA CD4 analyzer at 21 centers are plotted on Y axis and the counts obtained by the respective reference methods are plotted on X axis. Figure 1B: The agreement analysis using the Bland Altman plots. The percent relative bias for PIMA analyzer and the respective reference method is plotted on the Y axis and the average of the CD4 count by both the methods is plotted on X axis. The black line represents the mean% relative bias where as the blue lines represent the range of Mean ± SD.