Fig. 1

Unweighted linear regression (a) and Passing-Bablok regression (b) tests between CD4 T cell count measurements in 150 HIV-1-infected patients [including 124 adults (>19 years), 10 adolescents (10–19 years old), 13 children (>1 to 9 years) and 3 infants (<1 year)], expressed in absolute number (cells/µl) obtained in parallel by the Muse™ Auto CD4/CD4% system and by the reference BD FACSCount system. By unweighted linear regression, slope and Y-intercept values for the resultant trend line were 0.973 (95% CI, [+0.941 to +1.005]) and 9.0 (95% CI, [−14.0 to +31.9]), respectively. By Passing-Bablok regression, slope and Y-intercept values for the resultant trend line were 0.988 (95% CI, [+0.962 to +1.014]) and 8.1 (95% CI, [−1.8 to +16.2]), respectively. The diagonal dotted lines represent the ideal lines (no bias). The full lines represent the regression lines of the distribution