Comparing the percentage of CD4+ T cells in the stratum of CD4+ < 200 cells/mL by the hematology counter and flow cytometry showed that the measures have a strong correlation (r = 0.93). However, they do not show a good agreement, since the Bland-Altman plot (Figure 2(a)) shows that the difference between the two methods was 1.0% of CD4+ T selleckbio lymphocytes, and the limits of agreement were ��3.8%.To the stratum of CD4+ between 200 and 500 cells/mL, it is noted that the measures are moderately correlated (r = 0.65). Despite the correlation, Figure 2(b) (Bland-Altman) demonstrates broader limits of agreement of approximately 2.2 �� 13.5%. This is similar to the lymphocyte count above 500 cells/mL with limits of agreement approximately 6.2 �� 20.4%, as shown in Figure 3(b) (Bland-Altman), although this stratum showed a strong correlation (r = 0.

81). Similarly, MacLennan et al. [20], assessing the use of flow cytometry to provide only the absolute count of CD4+ T cells (associated with total lymphocyte count in hematology analyzers to obtain the percentage of CD4+ T lymphocytes), obtained bias of 0.92% and limits of agreement between 5.83% and 7.66% through FacsCount and Multitest/Tubs Trucount method and in FACSCalibur flow cytometer, for the absolute count of CD4+ T cells below 200 cells/mL.The main importance of using percentage values of CD4+ T lymphocytes is in the absolute count changes in response to stimuli that are independent of HIV infection, and the percentages are less subject to this variability [13].

Considering the percentage values of CD4+ T lymphocytes for evaluation of HIV-infected individuals, the stratum CD4+ < 200 cells/mL counting could be underestimated by up to 4.8% or overestimated up to 2.8%, while for the strata 200 < CD4+ < 500 cells/mL and CD4+ cells > 500 cells/mL, the count could be underestimated by up to 15.7% and 26.6% or overestimated by up to 11.4% and 14.1%, respectively, as presented in Figures Figures1,1, ,2,2, and and33.4. ConclusionsIn this study, the analysis of agreement between the hematology meter and the flow cytometer showed relatively large limits for the analyzed strata, indicating high variability.So, although there was a good correlation between the percentage values of CD4+ T lymphocytes estimated by the two methods association, the correlation between individual measurements indicated relatively large limits for Anacetrapib all strata of CD4+ cells studied.