Abstract
A total of 2,570 apparently healthy human immunodeficiency virus-negative adults from the six geopolitical zones in the country were enrolled in our study in 2006. The samples were assayed using the Cyflow technique. Data were analyzed using the Statistical Package for Social Scientists (SPSS). The majority (64%) of the participants had CD4 counts within the range of 501 to 1,000 cells/microl. The reference range for CD4 was 365 to 1,571 cells/microl, while the reference range for CD8 was 145 to 884 cells/microl.