Comparison of the new BD FACSCount® CD4 system
with Flowcare® PLG CD4 to measure absolute and percent CD4 cells in samples
from HIV positive Panamanian subjects
A.A. Martinez1, K.R. Page2, J.M. Pascale1, GORGAS Panamá.
1Gorgas Memorial Institute for Health Studies, Genomics, Panamá, Panama, 2Johns Hopkins University School of Medicine, Baltimore, United States
T cell count is a fundamental tool in HIV disease monitoring, but requires
costly equipment, reagents and specialized personnel. There is a need for
reliable systems than can be used in resource-limited settings. The goal of
this study was to compare the new BD FACSCount CD4 percent system with a
standard PLG system.
Methods: Samples from HIV+ subjects were processed, fixed, and run simultaneously in a BD FACSCount® for the BD FACSCount
percent CD4 system, and in a Beckman Coulter EPICS® XL for standard FlowCARE
CD4 PLG system. Statistical analysis was performed using correlation coeficient
(r), linear regression (R2), and Bland-Altman plot.
correlation and agreement were observed for samples of less than 1000 cells/µL (Table 1). Observed
values were, for Absolut CD4: R2:0.96,
y:0.4229 + 1.0093x, P< 0.001; and,
for CD4%: R2: 0.98, y:
25.22 + 0.8443x,
Different levels of
correlation and agreement were observed for absolute CD4 counts with the BD
FACSCount percent system depending on concentrations of CD4 cells/µL. Although
lower levels of correlation were observed for absolute values higher than 1000
cells/µL, this finding has minimal clinical implications. Correlation for percent values was excellent
at all CD4 counts. The good performance of the new BD FACSCount CD4 percent
reagent and its friendly and easy platform, make it suitable for monitoring
immune status in adults and children in resource limited settings.
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