has proven critical for the diagnosis and prognostication of HIV infection and the management of patients receiving anti-viral therapy Presently, most laboratories utilize three- or four-color immunophe notypic analysis for lymphocyte subset enumeration, with a CD45 side scatter gate to identify the lymphocyte population and to elimi nate dead cells, debris and degranulated granulocytes from analysis Three-color analysis is usually performed with two labeled specimens(i.e., CD45-CD 3-CD4 and CD45-CD3-CD8) while four-color analysis is performed with a single labeled specimen(i.e., CD45-CD3-CD4-CD8) n the past, the absolute lymphocyte count was separately deter mined on the hematology analyzer and then used in conjunction with flow cytometric data to calculate absolute CD4+ and CD8+ counts The accuracy of this analysis has been recently improved by introduc tion of methods that allow for direct measurement of absolute cell numbers with the flow cytometer only Studies of HIV-infected to a number of discoveries patients in the research laboratory have led awaiting widespread clinical utilization. At present, the most important is quantitative measurement of immune Some studies indicate CD38 expression superior to measurement tion of measurements of DNA ploidy or proliferation analysis. O Since 1996, the utilization of DNA analysis has significantly decreased, and breast car it is most often performed in patients with node-negative cinoma and other tumors where the clinical correlation is strongest innovations may lead to a revival of However, recent technological interest in clinical DNA analysis. In this regard, Bagwell modified DNA analysis to optimize the accuracy of DNA ploidy and S phase in node negative breast cancer, eliminate spurious technical inconsistencies and apply standardized modeling rules to data analysis and inter pretation. Furthermore, the authors developed a prognostic model that combines DNA ploidy and the S phase into a Relative Risk Index