Evaluation of PIMA TM H Point of Care Technology for CD4 T Cell Enumeration in Kenya Matilu Mwau 1 *, Ferdinard Adungo 1 , Silvia Kadima 1 , Ephantus Njagi 3 , Carolyne Kirwaye 1 , Najma Salim Abubakr 1 , Lucy Atsieno Okubi 1 , Mary Waihenya 1 , Judi Lusike 2 , Jackson Hungu 2 1 Kenya Medical Research Institute, Nairobi, Kenya, 2 Clinton Health Access Initiative, Nairobi, Kenya, 3 Deloitte Consulting LLC, Nairobi, Kenya Abstract CD4+ T cell enumeration is used to determine eligibility for antiretroviral therapy (ART) and to monitor the immune status of HIV-positive patients; however, many patients do not have access to this essential diagnostic test. Introducing point of care (POC) testing may improve access. We have evaluated Alere’s PIMA TM , one such POC device, against conventional CD4+ testing platforms to determine its performance and validity for use in Kenya. In our hands, Alere PIMA TM had a coefficient of variability of 10.3% and of repeatability of 175.6 cells/ml. It differed from both the BD FACSCalibur TM (r 2 = 0.762, mean bias 264.8 cells/ml), and the BD FACSCount TM (r 2 = 0.874, mean bias 7.8 cells/ml). When compared to the FACSCalibur TM at a cutoff of 350 cells/ml, it had a sensitivity of 89.6% and a specificity of 86.7% in those aged 5 years and over (Kw = 0.7566). With the BD FACSCount TM , it had a sensitivity of 79.4% and a specificity of 83.4% in those aged 5 years and over (Kw = 0.7790). The device also differed from PARTEC Cyflow TM (r 2 = 0.781, mean bias 224.2 cells/ml) and GUAVA TM (r 2 = 0.658, mean bias 20.3 cells/ml) platforms, which are used in some facilities in Kenya. We conclude that with refinement, Alere PIMA TM technology has potential benefits for HIV-positive patients. This study highlights the difficulty in selecting the most appropriate reference technology for technical evaluations. Citation: Mwau M, Adungo F, Kadima S, Njagi E, Kirwaye C, et al. (2013) Evaluation of PIMA TM H Point of Care Technology for CD4 T Cell Enumeration in Kenya. PLoS ONE 8(6): e67612. doi:10.1371/journal.pone.0067612 Editor: Philip J. Norris, Blood Systems Research Institute, United States of America Received November 5, 2012; Accepted May 21, 2013; Published June 25, 2013 Copyright: ß 2013 Mwau et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: Funding for this work was supported by the Kenya Medical Research Institute and the Clinton Health Access Initiative. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: Dr. Ephantus Njagi is an employee of Deloitte Consulting LLC. However, the company was not involved in any way in the conduct of this research. He participated in his capacity as an immunologist of repute with an interest in diagnostics. Therefore, his affiliation does not affect PLOS ONE policies on sharing data and materials. * E-mail: matilu.mwau@gmail.com Introduction CD4+ T cell quantification by flow cytometry is considered accurate, precise and reproducible [1,2]. A CD4+ T cell count is positively linked to long-term survival rates and indicates the level of immunosuppression[3–5]. During testing, patients older than five years of age are given an absolute CD4+ T cell count, which is determined as CD4+ cells/mL of blood. For patients five years old and younger, it is necessary to measure the percentage of CD4+ T cells among all lymphocytes [6]. Despite the fact that CD4+ T cell enumeration is essential in the initiation of antiretroviral therapy and the monitoring of care and treatment in Kenya, many HIV-positive patients still do not have reliable access to these services [7,8]. CD4 testing is often only available at centralized laboratories with significant infrastructure investments and highly skilled laboratory technicians [7]. Labo- ratory networking has improved access somewhat, but sample transportation networks are still so poor that many patients are unable to access adequate and necessary CD4 testing. Currently, CD4 testing using flow cytometry technology is available in many central and regional laboratories in Kenya using BD FACSCount TM or BD FACSCalibur TM (Becton Dickinson, Franklin Lakes, NJ, USA), PARTEC Cyflow TM (Partec GmbH, Munster, Germany), or GUAVA TM (EMD Millipore Corporation, Billerica, MA, USA) platforms. Unfortunately, this combination of technologies is insufficient to provide CD4 testing to all patients who need them. Long turn-around times for tests sent to central laboratories delay clinical decisions and put a considerable burden on patients. Conventional CD4 testing requires samples be transported in complicated and inefficient sample transportation networks and over long, rough roads. These transportation networks are limited and expensive, and are often compounded by the difficulties of short sample stability. Fortunately, high quality Point-Of-Care (POC) diagnostic technologies are promising solutions to critical CD4 testing needs in areas without existing laboratory capacity or easy access to conventional CD4 testing laboratories[9–13]. For example, HIV rapid diagnostic tests have increased patient access to HIV diagnosis in the last decade [14]. POC diagnostic technologies offer several advantages in that they are generally small, robust, relatively low cost, require little infrastructure, and require minimum technical skills. Additionally, replacement devices can be sent to a site immediately to sidestep POC device downtime. CD4 POC technologies can ease human resource capacity shortages and testing backlogs at central laboratories by diverting samples that are customarily referred. Most importantly, CD4 POC testing can allow doctors to make treatment decisions faster and achieve significant improvements in patient health outcomes. POC diagnostic technologies for HIV testing, viral load determination and CD4 enumeration are in various stages of development. PIMA TM (Alere Inc., Waltham, MA) is one such PLOS ONE | www.plosone.org 1 June 2013 | Volume 8 | Issue 6 | e67612