Skip to main content

Advertisement

Table 2 CD4 T cell counting in absolute count and percentage in 258 HIV-1-infected individuals, by the Apogee Auto40 flow cytometer at the hôpital Militaire D’Instruction, N’Djamena, Chad, and by the FACSCalibur at the hôpital de la Liberté, N’Djamena, at various CD4 T cell count ranges according to the FACSCalibur results

From: Single-platform, volumetric, CD45-assisted pan-leucogating flow cytometry for CD4 T lymphocytes monitoring of HIV infection according to the WHO recommendations for resource-constrained settings

Categories   < 200 cells/μl 200 – 350 cells/μl > 350 cells/μl
Number   N = 27 N = 43 N = 188
Absolute CD4 T cells (cells/ μl)*     
Apogee Auto40 Mean ± SD 118 ± 161 278 ± 129 2990 ± 3745
FACSCalibur Mean ± SD 100 ± 135 215 ± 103 3017 ± 3756
Absolute bias (limits of agreement)a Mean (±1.96 SD) −4.0 (−33.8;+25.8) 10.0 (−70.0;+90.0) 12.0 (−160.7;+184.7)
Relative (%) bias (limits of agreement)b Mean (±1.96 SD) 62.0 (−134.0;+258.0) 7.0 (−27.2;+41.2) −3.0 (−12.4;+6.4)
Percent CD4 T cells (%CD4)**     
Apogee Auto40 Mean ± SD 10.0 ± 12.7 19.5 ± 6.3 55.1 ± 44.5
FACSCalibur Mean ± SD 9.0 ± 11.3 18.0 ± 4.2 53.3 ± 41.7
Absolute bias (limits of agreement)a Mean (±1.96 SD) 1.0 (−1.8;+3.8) 2.0 (−2.3;+6.3) 2.0 (−3.4;+7.4)
Relative (%) bias (limits of agreement)b Mean (±1.96 SD) 6.0 (−10.3;+22.3) 7.0 (−13.2;+27.2) 2.0 (−4.6;+8.6)
  1. * Results in absolute CD4 T cell counts by Auto40 and FACSCalibur were correlated using the non-parametric Passing–Bablok regression analysis (< 200 cells/μl: r = 0.86, slope = 1.11, intercept = −12.0; 200 – 350 cells/μl: r = 0.68, slope = 1.31, intercept = −96.5; > 350 cells/μl: r = 0.98, slope = 1.02, intercept = −24.8);
  2. ** Results in percentage CD4 T cell counts by Auto40 and FACSCalibur were correlated using the non-parametric Passing–Bablok regression analysis (< 200 cells/μl: r = 0.89, slope = 1.00, intercept = 0.0; 200 – 350 cells/μl: r = 0.89, slope = 1.00, intercept = 0.0; > 350 cells/μl: r = 0.95, slope = 1.00, intercept = 0.0);
  3. a The Bland Altman analysis was carried out to calculate the absolute bias and limits of agreement which are the 95% confidence intervals (±1.96 × SD) of the mean bias of all paired measurements in a given category [27];
  4. b The Pollock analysis was carried out to calculate the relative bias and limits of agreement which are the 95% confidence intervals (±1.96 × SD) of the mean bias of all paired measurements in a given category [28].
  5. SD: Standard deviation.