Systems for the staging of individuals with human immunodeficiency virus type 1 (HIV-1) infection were developed 15 years ago. Subsequently, assays for quantitating HIV-1 RNA and immunophenotyping of lymphocyte subsets have been developed and validated. The utility of these assays for improved staging in early disease was evaluated in 256 HIV-infected adults (52% minority) with CD4 counts > or = 400 cells/microL followed in U.S. military medical centers before the highly active anti-retroviral therapy era. HIV viral load (RNA) was quantitated; the frequencies of select CD4+ immunophenotypes were determined in 112 subjects. The results were analyzed in relation to three outcome measures: death, first acquired immunodeficiency syndrome-defining opportunistic infection, and CD4 count < or = 200 cells/microL. Serum RNA level and CD4 count were each found to be predictive of all three outcomes. In addition, increases in the T-cell subsets CD28-CD4+ and CD29+CD26-CD4+ were found to be independently predictive of more rapid progression. The classification of early-stage HIV patients is improved by the quantitation of both viral RNA and T-lymphocyte subsets.