['To determine the reference ranges of lymphocyte subsets in serologically HIV-seronegative healthy male adults in Oman.', 'A cohort, of 118 healthy male blood donors ranging in age from 18-51 years, was included in the study. The average age was 25 years. Blood samples collected into tubes containing ethylene-diamine-tetra acetic acid were investigated for lymphocyte subsets using flow cytometer. This study was conducted in the Immunology Laboratory of the Sultan Qaboos University, College of Medicine and Health Sciences, Muscat, Oman during the year 2006.', 'For the 118 males investigated, the mean percentage and absolute values of the lymphocyte subsets were as follows: CD3: 68.53 +/- 7.5%, 1701 +/- 489 cells/microliter; CD4: 40.4 +/- 6.5%, 1006 +/- 319 cells/microliter; CD8: 25.8 +/- 5.9%, 638 +/- 225 cells/microliter; CD19: 13.7 +/- 4.7%, 349 +/- 158 cells/microliter, and CD56: 12.2 +/- 6.7%, 308 +/- 204 cells/microliter. The ratio of CD4/CD8 was 1.6.'] Does reference range for lymphocyte subsets in healthy adult male Omanis?