The use of glutaraldehyde-fixed chicken red blood cells as counting beads for performing affordable single-platform CD4+ t-lymphocyte count in HIV-1-infected patients

Abstract

CD4 T-lymphocyte count is an important marker in management of HIV-1-infected patients. The standard single-platform (SP) flow cytometric (FCM) CD4 testing that uses the known reference microbeads is expensive; more affordable alternatives are therefore needed. We evaluated the use of glutaraldehyde-fixed chicken red blood cells (CRBCs) as counting beads as an alternative for enumerating CD4 T-lymphocyte counts in 87 HIV-1-infected patients. Linear regression analyses revealed an excellent correlation of the SP FCM using CRBCs with the standard SP bead-based FCM method (percentages, r > 0.99; absolute counts, r > 0.98) over the entire range including the clinically relevant range. Mean percent bias for the CRBC method was +0.35% [limits of agreement (LOA):-1.86% to +2.57%]. For absolute CD4 T-lymphocytes, the mean biases was-47.76 cells per microliter (LOA:-191.34 to +98.81 cells/μL) with much lower bias for CD4 T-lymphocyte counts <200 cells per microliter (LOA:-31.92 to +22.95 cells/μL). The use of CRBCs is comparable with the use of commercial microbeads. This has resulted in major cost savings to resource-limited countries where the health care system is under increasing pressure to operate cost effectively. This can greatly facilitate and ensure the success of the ongoing antiretroviral therapy program in these countries. Copyright © 2009 by Lippincott Williams & Wilkins.