Open Access Validation of Microcapillary Flow Cytometry for Community-Based CD4+ T Lymphocyte Enumeration in Remote Burkina Faso

Abstract: Background: CD4+ T lymphocyte enumeration plays a critical role in the initiation and monitoring of HIV-infected patients on antiretroviral therapy. There is an urgent need for low-cost CD4+ enumeration technologies, particularly for use in dry, dusty climates characteristic of many small cities in Sub-Saharan Africa. Design: Cross-sectional study Methods: Blood samples from 98 HIV-infected patients followed in a community HIV clinic in Ouahigouya, Burkina Faso were obtained for routine CD4+ T lymphocyte count monitoring. The blood samples were divided into two aliquots, on which parallel CD4+ measurements were performed using microcapillary (Guava EasyCD4) and dedicated (Becton Dickinson FACSCount) CD4+ enumeration systems. Spearman rank correlation coefficient was calculated, and the sensitivity, specificity and positive predictive value (PPV) for EasyCD4 <200 cells/L were determined compared to the reference standard FACSCount CD4 <200 cells/L. Results: Mean CD4 counts for the EasyCD4 and FACSCount were 313.75 cells/L and 303.47 cells/L, respectively. The Spearman rank correlation coefficient was 0.92 (p<0.001). Median values using EasyCD4 were higher than those with the FACSCount (p=0.004). For a CD4<350 cells/uL, sensitivity of the EasyCD4 was 93.9 % (95%CI 85.2-98.3%), specificity was 90.6 % (95 % CI 75.0-98.0%), and PPV was 95.4 % (95%CI 87.1-99.0%). Conclusion: Use of the EasyCD4 system was feasible and highly accurate in the harsh conditions of this remote city i