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.