Abstract

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

Background: CD4+ 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.
Results: Good 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, P< 0.001.
[tab_01]
Conclusions:
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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