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
Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, 30190-002, Brazil.
Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602-7387, USA.
Trans R Soc Trop Med Hyg. 2018 Jan 1;112(1):1-7. doi: 10.1093/trstmh/try014.
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.
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.
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.
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.
在消除血吸虫病之前，必须致力于实现准确、快速的个体诊断。在低流行地区，寄生虫学诊断和即时检测循环阴极抗原（POC-CCA）诊断仍然不准确。
我们团队对POC-CCA进行了优化，增加了一个30分钟的尿液浓缩步骤，无需专业技术人员或设备，且准确性高。我们在巴西两个不同特征的流行地区对这种名为POC-CCA过滤器（FLT）的新方法进行了评估。
在基线时，POC-CCA表现不佳，出现了几个错误结果和不确定的微量读数，显示患病率为10%，而POC-CCA FLT的患病率为23%，与寄生虫学诊断率相似。在一个地区，尿液浓缩后准确性从低至0.36提高到了0.96。在三个治疗后时间点，POC-CCA仅正确诊断了一半的病例，而POC-CCA FLT分别能够诊断96%、83%和100%的病例。
通过快速简单的尿液浓缩步骤改进传统POC方法，不仅提高了吡喹酮治疗前后的准确性，还保留了其在低流行地区的适用性，能够将微量读数定义为阴性病例。
