Abstract
A previous study carried out in a tertiary care hospital in Colombia demonstrated the usefulness of the Cryptococcus capsular antigen detection by latex (CrAg Latex) in the early diagnosis of cryptococcosis in HIV-infected patients with low CD4 + levels. The aim of this study was to establish the performance of a new rapid lateral flow assay (CrAg LFA) in preserved sera of those HIV-infected patients collected between 2001 and 2006. A total of 421 sera from 297 patients with a confirmed diagnosis of HIV were tested with CrAg LFA and results compared with those obtained with CrAg Latex. All patients provided informed consent for specimen collection. A concordance of 100% was found between positive results obtained by both methods. However, 13 sera that were negative by CrAg Latex, were positive by CrAg LFA (3.1%). In these positive patients, median of CD4 + levels was 67 cells/μl (8–608 cells/μl), while median of viral load was 118,965 copies/ml (50–500,000 copies/ml). Patients who were negative for cryptococcosis had a median of 177 cells/μl in CD4 + levels (4–2516 cells/μl) and a median of 62,318 copies/ml in viral loads (25–50,000 copies/ml). A significant statistical difference was found when comparing CD4 + levels and viral load in patients positive for cryptococcosis and those that were proven to be negative (P < 0.0001). The use of Point-of-Care Tests (POCT) like CrAg LFA play an important role in the diagnosis of infectious diseases, especially in resource limited settings, where it will be a useful means to diagnose cryptococcosis early in HIV patients.
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Acknowledgments
The authors acknowledge IMMY, for the donation of the lateral flow immunoassay CrAg LFA kits for this study. All authors were involved in collection of data, data analysis and writing and review of the manuscript. J.L., P.E. and E.C. were the primary leaders on this manuscript. C.I.A. was involved in data cleaning, data analysis and writing and review of the manuscript. T.C. was involved in review of the data analysis and review of the manuscript.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of the paper. The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the Centers for Disease Control and Prevention.
This work was supported by the Hospital Universitario Erasmo Meoz in Cúcuta, Colombia, and the Instituto Nacional de Salud, Bogotá, D.C., Colombia.
This paper was first published online on Early Online on 18 April 2013.