Successful implementation of a low-cost method for enumerating CD4 T lymphocytes in resource-limited settings: the ANRS 12–26 study Serge Diagbouga a , Corine Chazallon b , Michel D. Kazatchkine c , Philippe Van de Perre d , Andre ´ Inwoley e , Souleymane M’Boup f , Mireille Prince David g , Aoua Thie ´ro Te ´nin h , Robert Soudre ´ i , Jean-Pierre Aboulker b and Laurence Weiss c Objective: To evaluate the feasibility and the relevance of the implementation of an alternative technique to flow cytometry (FC) for enumerating CD4 T cells (Dynabeads; Dynal Biotech, Oslo, Norway), based on quantifying CD4 T cells by epifluorescent microscopy following their isolation using anti-CD4 monoclonal antibody-coated magnetic beads. Design: International multi-center study. Five consecutive runs of dual CD4 T-lympho- cyte enumeration by both techniques in six sites in five countries of West Africa. Methods: A total of 657 pairs of values of CD4 cell counts were generated by 43 technicians by both FC (TruCount; Becton Dickinson Immunocytometry Systems, San Jose, California, USA) and Dynabeads from blood samples obtained from 301 HIV- infected patients, seen in one (n ¼ 112), two (n ¼ 61), three (n ¼ 75), four (n ¼ 40) or five (n ¼ 13) occasions. Results: The correlation coefficient between the results of the two techniques was 0.89. The overall systematic difference between Dynabeads and FC was 16 3 10 6 cells/l (P , 10 4 ). The median difference was insignificant (+7.5 cells) for CD4 cell counts below 200 3 10 6 cells/l and increased with CD4 levels. Patients were consistently classified at the threshold of 200 3 10 6 cells/l by both methods in 88.7% of cases. Among the 74 discrepant pairs of values, only 31 (4.7%) exhibited a difference of more than 100 3 10 6 cells/l. Conclusions: Results from Dynabeads and FC were highly correlated. The ability of the alternative method to consistently classify results in agreement with FC, at thresh- olds of CD4 cell counts relevant for clinical care, was high. The implementation of this low-cost method was easy and successful in the West African context. & 2003 Lippincott Williams & Wilkins AIDS 2003, 17:2201–2208 Keywords: HIV, human, CD4 lymphocyte count, methods, flow cytometry, developing countries, Africa Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. From the a Centre Muraz, Bobo-Dioulasso, Burkina Faso, b INSERM SC10, Villejuif, c Ho ˆ pital Europe ´en Georges Pompidou, Universite ´ Pierre et Marie Curie and INSERM U430, Paris, France, d Arnaud de Villeneuve Hospital, Montpellier, France, e CeDReS, Abidjan, Co ˆ te d’Ivoire, f Ho ˆpital Aristide Le Dantec, Dakar, Se ´ne ´gal, g CHU Campus, Lome ´, Togo and h INRSP, Bamako, Mali, i Faculte ´ de Me ´decine, Ouagadougou, Burkina Faso. Correspondence to Serge Diagbouga, Centre Muraz, PO Box 390, Bobo-Dioulasso, Burkina Faso. E-mail: diagbouga_serge@hotmail.com Received: 10 December 2002; revised: 7 April 2003; accepted: 14 April 2003. DOI: 10.1097/01.aids.0000088198.77946.5e ISSN 0269-9370 & 2003 Lippincott Williams & Wilkins 2201