Journal of Immunobiology

Evaluation of Three Medium Throughput Flow Cytometers for Monitoring People Living with HIV in Resources Limited Laboratories: How to Choose?

Abstract

André Inwoley, Aimé Cézaire Adiko, Mathieu Kabran, Roséline Aboli-Affi, Ahmed Diomande, Franck Wozan and Bamory Dembele

Objective: Absolute and percentage CD4+ T-lymphocytes counts are useful in monitoring people living with HIV. In spite of point-of-care development, CD4 testing in some laboratories of resources-limited countries still use flow cytometers from many manufacturers. We evaluated three flow cytometers (FACSCOUNT CD4/CD4%, GUAVA Auto CD4/CD4%, CYFLOW Counter® CD4/CD4%) and brought out choice criteria according to laboratory resources. Methods: CD4 percent and absolute count obtained with 180 HIV-infected patients (adults and children) with evaluated platforms (FACSCOUNT CD4/CD4%, GUAVA Auto CD4/CD4%, CYFLOW Counter CD4/CD4%) were compared with those provided by FACSCalibur TruCount®. Agreement was analyzed using Bland-Altman analysis. We also carried out a Comparative analysis of technical and operational characteristics to identify strengths and weaknesses of each tested cytometer. Results: The median CD4 percentage and absolute count obtained with FACSCOUNT and CYFLOW were similar to those of FACSCALIBUR. By contrast, GUAVA showed higher values. Bland-Altman analysis did not show measurement error. However, GUAVA and CYFLOW gave a relative high bias with mean difference respectively -69 and +27CD4 cells/μl. The overall bias of CD4 percentage were >5% for the evaluated cytometers. There was a good interclass agreement (Kappa ≥ 0.78) and good measurement precision (coefficient of variation <10%) with the 3 cytometers. Only FACSCOUNT showed good stability (CV<5%) even for stained and unstained samples within 24 and 48 hours after blood collection. FACSCOUNT, GUAVA and CYFLOW have good technical performances. Conclusion: Though we found differences in their operational characteristics, it appears very important to know how to use these kinds of cytometers before making a choice for peripheral laboratory in limited-resources countries.