Abstract:
Background: CD4+ T-lymphocyte count (CD4 count) is a standard method used to monitor HIV-infected patients during
anti-retroviral therapy (ART). The World Health Organization (WHO) has pointed out or recommended that a handheld,
point-of-care, reliable, and affordable CD4 count platform is urgently needed in resource-scarce settings.
Methods: HIV-infected patient blood samples were tested at the point-of-care using a portable and label-free microchip
CD4 count platform that we have developed. A total of 130 HIV-infected patient samples were collected that included 16
de-identified left over blood samples from Brigham and Women’s Hospital (BWH), and 114 left over samples from Muhimbili
University of Health and Allied Sciences (MUHAS) enrolled in the HIV and AIDS care and treatment centers in the City of Dar
es Salaam, Tanzania. The two data groups from BWH and MUHAS were analyzed and compared to the commonly accepted
CD4 count reference method (FACSCalibur system).
Results: The portable, battery operated and microscope-free microchip platform developed in our laboratory (BWH) showed
significant correlation in CD4 counts compared with FACSCalibur system both at BWH (r = 0.94, p,0.01) and MUHAS
(r = 0.49, p,0.01), which was supported by the Bland-Altman methods comparison analysis. The device rapidly produced
CD4 count within 10 minutes using an in-house developed automated cell counting program.
Conclusions: We obtained CD4 counts of HIV-infected patients using a portable platform which is an inexpensive (,$1
material cost) and disposable microchip that uses whole blood sample (,10 ml) without any pre-processing. The system
operates without the need for antibody-based fluorescent labeling and expensive fluorescent illumination and microscope
setup. This portable CD4 count platform displays agreement with the FACSCalibur results and has the potential to expand
access to HIV and AIDS monitoring using fingerprick volume of whole blood and helping people who suffer from HIV and
AIDS in resource-limited settings.
