Evaluation of a manual CD4+ count kit for determination of absolute CD4+ T-lymphocyte counts.

OBJECTIVE: The aim of the present study was to evaluate a manual CD4+ count kit assay (CD4+: cytospheres) for CD4+ T-lymphocyte count compared with flow cytometric method in HIV infected patients. MATERIAL AND METHOD: One hundred thirty three HIV infected patients were recruited from the out patient department of Khon Kaen Hospital. Blood samples were done by a manual CD4+ count kit assay (CD4+: cytospheres) and flow cytometry for CD4+ T-lymphocyte count. The data were analyzed for diagnostic test and correlation coefficient. RESULTS: The data of cytospheres assay and flow cytomeric method showed good correlation (r = 0.88) for the total group. At the absolute CD4+ T-lymphocyte 200 cells/cu.mm, the cytospheres assay demonstrated sensitivity 83.10% (76.73-89.47%), specificity 93.55% (89.37-97.72%), PPV 93.65% (89.51-97.79%), NPV 82.86% (76.45-89.26%). In the case of CD4+ T-lymphocyte count were lower than 200 cells/cu.mm, the cytospheres assay displayed progressive decrease in sensitivity successive increase in specificity. CONCLUSION: The cytospheres technique is an alternative noncytofluorometric assay for CD4+ T-lymphocyte count. This test may be useful for screening in HIV infected adult patients in community hospitals where flow cytometry technique is not available. But the assay is limited in determination only absolute CD4+ T-lymphocyte count with higher than 30 cells/cu.mm. This technique is not benefit in pediatric HIV/AIDS patient due to percentage CD4+ value did not obtained. The quality control should be concern technical skill and proficiency testing for laboratory setting.

Total lymphocyte count: a surrogate marker for predicting CD4+ count in enrolled process for antiretroviral therapy in resource-limited settings.

OBJECTIVE: The purpose of the present study was to evaluate the correlation between total lymphocyte count (TLC) and CD4+ count and TLC cut-off for predicting CD4+ count < 200 cells/mm3. MATERIAL AND METHOD: The 176-naïve HIV-infected patients from the OPD Khon Kaen Hospital, were recruited for CD4+ count by flow cytometer and TLC by automated cell counter. All results were analyzed by STATA statistical software for sensitivity, specificity, PPV and NPV. RESULTS: From 176 patients, 61 (34.7%) had CD4+ > 200 cells/mm3 and 115 (65.3%) had CD4+ < 200 cells/mm3. The ROC curve between CD4+ count and TLC showed TLC < 1,800 cells/mm3 could predict CD4+ count < 200 cells/mm3 with 78.26% sensitivity, 73.77% specificity, 84.91% PPV, and 64.29% NPV. The sensitivity was further decreased and specificity was increased when TLC was lower than cut-off. CONCLUSION: The presented finding indicates that the appropriated TLC for predicting CD4+ count. < 200 cells/mm3 was TLC < 1,800 cells/mm3. TLC can also be used as a surrogate marker for starting ARV therapy in resource limited setting.