COMPARISON OF ABSOLUTE CD4(-IMMUNOASSAY (TRAX CD4 TEST KIT) AND FLOW-CYTOMETRY() LYMPHOCYTE COUNTS DETERMINED BY ENZYME)

Currently, CD4(+) lymphocyte counts are one of the most widely used su rrogate markers for monitoring disease progression in and initiating t herapy for human immunodeficiency virus-infected individuals, However, the process of obtaining lymphocyte subset counts can be complex and expensive, often rendering the test inaccessible to many patients, In contrast to standard laser-based flow cytometry, the TRAx CD4 Test Kit utilizes an enzyme-linked immunoassay format to provide CD4(+) lympho cyte counts by a simple and more cost-effective means. In order to eva luate the utility of the TRAx CD4(+) assay in comparison,vith flow cyt ometry, heparinized blood samples were drawn from 188 infected and uni nfected adult patients and 24 infected pediatric patients and evaluate d by both assays. The correlation coefficient for all adult individual s tested was 0.94, and the mean absolute counts (in cells per millilit er, +/- standard deviation) were 510 +/- 358 for TRAx and 480 +/- 361 for how cytometry, The correlation for the pediatric group was 0.93, w ith mean absolute counts of 956 +/- 767 for TRAx and 1,521 +/- 1,438 f or flow cytometry. Overall the TRAx CD4 Test Kit performed well in com parison to flow cytometry, and its lower cost and ease of use make it an encouraging alternative for the routine determination of CD4(+) lym phocyte counts.