Bergeron M., Daneau G., Ding T., Sitoe N.E., Westerman L.E., Stokx J., Jani I.V., Coetzee L.M., Scott L., de Weggheleire A., Boel L., Stevens W.S., Glencross D.K., Peter T.F.
Public Health Agency of Canada, National Laboratory for HIV Immunology, Ottawa, Canada; Immunology Unit, Institute of Tropical Medicine, Antwerp, Belgium; Instituto Nacional da Saúde, Maputo, Mozambique; Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Atlanta, GA, United States; Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; University of the Witwatersrand, Faculty of Health Science, School of Pathology, Johannesburg, South Africa; Clinton Health Access Initiative, Maputo, Mozambique
Bergeron, M., Public Health Agency of Canada, National Laboratory for HIV Immunology, Ottawa, Canada; Daneau, G., Immunology Unit, Institute of Tropical Medicine, Antwerp, Belgium; Ding, T., Public Health Agency of Canada, National Laboratory for HIV Immunology, Ottawa, Canada; Sitoe, N.E., Instituto Nacional da Saúde, Maputo, Mozambique; Westerman, L.E., Division of Global HIV/AIDS, Centers for Disease Control and Prevention, Atlanta, GA, United States; Stokx, J., Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Jani, I.V., Instituto Nacional da Saúde, Maputo, Mozambique; Coetzee, L.M., University of the Witwatersrand, Faculty of Health Science, School of Pathology, Johannesburg, South Africa; Scott, L., University of the Witwatersrand, Faculty of Health Science, School of Pathology, Johannesburg, South Africa; de Weggheleire, A., Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium; Boel, L., Immunology Unit, Institute of Tropical Medicine, Antwerp, Belgium; Stevens, W.S., University of the Witwatersrand, Faculty of Health Science, School of Pathology, Johannesburg, South Africa; Glencross, D.K., University of the Witwatersrand, Faculty of Health Science, School of Pathology, Johannesburg, South Africa; Peter, T.F., Clinton Health Access Initiative, Maputo, Mozambique
Introduction: Point-of-care (POC) CD4 testing can improve access to treatment by enabling decentralization and reducing patient loss-to-follow-up. As new POC CD4 technologies become available, their performance should be assessed before widespread deployment. This study reports the findings of five independent evaluations of the PointCare NOW CD4 system. Materials/Methods: Evaluations were conducted in Southern Africa (Mozambique, South Africa) and North America (Canada, USA). 492 blood samples (55 from HIV-negative blood donors and 437 from HIV-infected patients, including 20 children aged between 12 and 59 months) were tested with both the PointCare NOW and reference flow cytometry instruments. Assessment of bias, precision and levels of clinical misclassification for absolute and percent CD4 count was conducted. Results: PointCare NOW significantly overestimated CD4 absolute counts with a mean relative bias of +35.0%. Bias was greater in samples with CD4 counts below ≤350cells/μl (+51.3%) than in the CD4 >350cells/μl stratum (15.1%). Bias in CD4% had a similar trend with an overall relative mean bias of +25.6% and a larger bias for low CD4 stratum (+40.2%) than the higher CD4 stratum (+5.8%). Relative bias for CD4% in children was -6.8%. In terms of repeatability, PointCare NOW had a coefficient of variation of 11%. Using a threshold of 350cells/μl, only 47% of patients who qualified for antiretroviral therapy with reference CD4 testing, would have been eligible for treatment with PointCare NOW test results. This was 39% using a 200cells/μl threshold. Agreement with infant samples was higher, with 90% qualifying at a 25% eligibility threshold. Conclusion: The performance of the PointCare NOW instrument for absolute and percent CD4 enumeration was inadequate for HIV clinical management in adults. In children, the small sample size was not large enough to draw a conclusion. This study also highlights the importance of independent evaluation of new diagnostic technology platforms before deployment. © 2012 Passmore et al.