Evaluation of a single‐platform microcapillary flow cytometer for enumeration of absolute CD4+ T‐lymphocyte counts in HIV‐1 infected Thai patients

Abstract

Background: Various assays are used to enumerate peripheral blood absolute CD4+ T-lymphocytes. Flow cytometry is considered the gold standard for this purpose. However, the high cost of available flow cytometers and monoclonal antibody reagents make it difficult to implement such methods in the resource-poor settings. In this study, we evaluated a cheaper, recently developed single-platform microcapillary cytometer for CD4+ T-lymphocyte enumeration, the personal cell analyzer (PCA), from Guava V V R Technologies. Methods: CD4+ and CD8+ T-lymphocyte counts in whole blood samples from 250 HIV-1 infected Thais were determined, using a two-color reagent kit and the Guava PCA, and compared with the results obtained with two reference microbead-based methods from Becton Dickinson Biosciences: the threecolor TruCOUNT TM tube method and the two-color FACSCount TM method. Statistical correlations and agreements were determined using linear correlation and Bland-Altman analysis.Results: Absolute CD4+ T-lymphocyte counts obtained using the Guava PCA method highly correlated with those obtained using TruCOUNT method (R 2 = 0.95, mean bias +13.1 cells/ml, limit of agreement [LOA] 2117.9 to +144.1 cells/ml) and the FACSCount method (R 2 = 0.94, mean bias = +33.2 cells/ml, LOA 2101.8 to +168.3 cells/ml). Absolute CD8+ T-lymphocyte counts obtained using the Guava PCA method also highly correlated with those obtained with the two reference methods (R 2 = 0.92 and 0.88, respectively).Conclusion: This study shows that the enumeration of CD4+ T-lymphocytes using the Guava microcapillary cytometer PCA method performed well when compared with the two reference bead-based methods. However, like the two reference methods, this new method needs substantial technical expertise. q 2007 Clinical Cytometry Society

Evaluation of Three Medium Throughput Flow Cytometers for Monitoring People Living with HIV in Resources Limited Laboratories: How to Choose?

“…In addition, absolute bias increases between Guava® and FACSCalibur® from low to higher strata. Our results confirmed previous studies reporting that Guava® is less accurate at CD4 counts above 500 cells/μl [16,20,21,31]. This difference could be caused by the way of separating monocyte and lymphocyte count which share CD4 on cell surface.…”

“…Many flow cytometers have been tested [16][17][18][19][20][21][22][23][24]. However, some of this first generation has a few limitations: (i) it was not possible to get CD4 percentage which is very important in children monitoring or (ii) the use of FCM software requires good computer skills by the operator.…”

Comparison of 5 Flow Cytometric Immunophenotyping Systems for Absolute CD4+ T-Lymphocyte Counts in HIV-1-Infected Patients Living in Resource-Limited Settings

“…There have been several studies, including our own, which showed that these 2 new volumetric technologies performed well in comparison with the performance of the standard SP bead-based FCM method. [16][17][18][19] The low cost of testing by these 2 new FCMs has already increased access to CD4 testing, particularly for HIV-1-infected persons living in developing countries or in resource-limited settings.…”

Research needs and challenges in the development of HIV diagnostic and treatment monitoring tests for use in resource-limited settings

“…It may be necessary for each region to develop its own CD4 cell count criteria for initiating ART and prophylaxis against opportunistic infections. Table 1 [21,[23][24][25][26][27][29][30][31][32][33][99][100][101] provides an example of the current situation regarding research into alternative technologies for treatment initiation and monitoring. This table summarizes the research efforts invested to date into field evaluation of newer automated technologies to enumerate CD4 cell counts.…”