Monitoring of human immunodeficiency virus infection in resource-constrained countries.
The reference standards used to monitor human immunodeficiency virus (HIV) infection are flow cytometric analysis of T lymphocyte subsets to provide the CD4+ T cell count and molecular assays to quantify plasma HIV load. Few laboratories in resource-constrained countries can afford to perform these tests. A number of lower-cost assays requiring less expensive equipment may be well-suited to such countries. These include manual CD4 cell assays (Dynal, Coulter, BioRad) and ultrasensitive reverse transcriptase (Cavidi) and p24 (Perkin Elmer Life Sciences) assays to monitor virus load. Quality control and access to quality assurance programs are essential. The total lymphocyte count, although readily available and inexpensive, generally does not correlate as closely with CD4+ T cell counts. Other surrogate markers, such as beta2-microglobulin, are not suitable for routine monitoring of HIV infection. This review discusses the above assays and their role in addition to clinical monitoring in resource-constrained countries.