Innovative methodology for point-of-care circulating cathodic antigen with rapid urine concentration for use in the field for detecting low Schistosoma mansoni infection and for control of cure with high accuracy

• Published in: Transactions of the Royal Society of Tropical Medicine and Hygiene Vol. 112; no. 1; pp. 1 - 7
• Main Authors: Grenfell, Rafaella F Q, Taboada, Diana, Coutinho, Lucélia A, Pedrosa, Maria Luysa C, Assis, Jéssica V, Oliveira, Matheus S P, Cruz, Renata R, Almeida, Aureo, Silva-Moraes, Vanessa, Katz, Naftale, Coelho, Paulo Marcos Z
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2018
• Subjects: Schistosomiasis mansoni; Control of cure; Fast urine concentration; Trace readings definition; Cross-reactivity; POC-CCA improvement
• ISSN: 0035-9203; 1878-3503
• DOI: 10.1093/trstmh/try014

Abstract Background Prior to eliminating schistosomiasis, efforts must address accurate and fast individual diagnosis. Diagnosis is still inaccurate by parasitological and point-of-care circulating cathodic antigen (POC-CCA) in areas of low endemicity. Methods Our group has optimized POC-CCA with a 30 min urine concentration step with no need for specialized technicians or equipment and with high accuracy. We evaluated this new method, called POC-CCA filter (FLT), in two Brazilian endemic areas with distinct profiles. Results At baseline, POC-CCA had a poor performance with several false results and undefined trace readings, revealing a prevalence rate of 10% against a rate of 23% for POC-CCA FLT, which was similar to the parasitological rates. Accuracy increased from as low as 0.36 to 0.96 after urine concentration in one area. POC-CCA properly diagnosed only half of the cases at three post-treatment time points, while POC-CCA FLT was able to diagnose 96, 83 and 100%, respectively. Conclusions The improvement of conventional POC methodology by a fast and simple urine concentration step provided not only an increase in its accuracy before and after praziquantel treatment, but also preserved its applicability in low-prevalence endemic areas, allowing the definition of trace readings as negative cases.