Comparative assessment of five alternative methods for CD4+ T-lymphocyte enumeration for implementation in developing countries.

This study compares five alternative methods with regard to the accuracy of CD4+ cell counts measured at the same time by standard flow cytometry (FC). The alternative methodologies studied included: FACSCount; VCS Technology/Coulter Cytospheres; Dynabeads MPC-Q; Capcellia; and Opti-CIM. These methods were performed simultaneously on the blood samples of 40 HIV-infected patients and 20 healthy adult employees collected on 4 separate days. Overall findings revealed that the correlation coefficients between results obtained by FC and each alternative method were similar whatever the range of CD4+ cell count (> or < 500/cu. mm) except for Capcellia. The median differences between absolute numbers of CD4+ T lymphocytes obtained by standard FC and each alternative method were 45 (n = 45) for FACSCount 56 (n = 46) for Dynabeads 195 (n = 55) for Cytospheres 134 (n = 49) for Capcellia and 126 (n = 27) for Opti-CIM. The study showed that FACSCount equipment was lowest compared with the other methods with regard to the median difference in absolute numbers of CD4+ T lymphocytes. Moreover it was also determined that with Dynabeads when compared with the standard FC method an excellent correlation coefficient was found without regard to the CD4+ cell number. In conclusion the FACSCount and Dynabeads methods compared well with standard FC irrespective of CD4+ cell numbers. The Dynabeads method appears to be less expensive hence it has potential in countries with limited economic resources.