Universidade do Estado do Pará, Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia, Belém, PA, Brasil.
Instituto Evandro Chagas/SVS/MS, Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia, Secção de Parasitologia, Ananindeua, PA, Brasil.
Rev Soc Bras Med Trop. 2020 Sep 25;53:e20190562. doi: 10.1590/0037-8682-0562-2019. eCollection 2020.
Schistosomiasis is a poverty-related disease that affects people in 78 countries worldwide. This study aimed to evaluate the point-of-care circulating cathodic antigen (POC-CCA) test performance using sensitive parasitological methods as a reference standard (RS) in individuals before and after treatment.
The RS was established by combining the results of 16 Kato-Katz slides and the Helmintex® method. Positivity rates of the POC-CCA test and Kato-Katz and Helmintex® methods were calculated before treatment and 30 days afterward. Furthermore, the sensitivity, specificity, accuracy, and kappa coefficient before treatment were determined by comparing the methods. The cure rate was defined 30 days after treatment.
Among the 217 participants, the RS detected a total of 63 (29.0%) positive individuals. The POC-CCA test identified 79 (36.4%) infections. The evaluation of POC-CCA test performance in relation to the RS revealed a sensitivity of 61.9%, specificity of 74.0%, accuracy of 70.5%, and kappa coefficient of 0.33. Out of the 53 remaining participants after treatment, a total of 45 (81.1%) showed egg negative results, and 8 (18.9%) were egg positive according to the RS. A total of 5 (9.4%) egg-positive and 37 (69.8%) egg-negative individuals were positive by the POC-CCA test.
Our data show that the POC-CCA test has potential as an auxiliary tool for the diagnosis of Schistosoma mansoni infection, yielding better results than 16 Kato-Katz slides from three different stool samples. However, the immunochromatographic test lacks sufficient specificity and sensitivity for verifying the cure rate after treatment.
血吸虫病是一种与贫困相关的疾病，影响着全球 78 个国家的人群。本研究旨在评估在治疗前后，使用以灵敏的寄生虫学方法为参考标准（RS）的即时检测循环阴离子抗原（POC-CCA）试验在个体中的性能。
RS 通过结合 16 张加藤厚涂片和 Helmintex®方法的结果建立。在治疗前和治疗后 30 天，计算 POC-CCA 试验和加藤厚涂片和 Helmintex®方法的阳性率。此外，通过比较方法，确定治疗前 POC-CCA 试验的灵敏度、特异性、准确性和 Kappa 系数。将治疗后 30 天的治愈率定义为。
在 217 名参与者中，RS 共检测到 63 例（29.0%）阳性个体。POC-CCA 试验检测到 79 例（36.4%）感染。与 RS 相比，评估 POC-CCA 试验性能的结果显示，灵敏度为 61.9%，特异性为 74.0%，准确性为 70.5%，Kappa 系数为 0.33。治疗后剩余的 53 名参与者中，共有 45 名（81.1%）粪便中虫卵阴性，45 名（81.1%）根据 RS 显示虫卵阳性。POC-CCA 试验检测到 5 名（9.4%）虫卵阳性和 37 名（69.8%）虫卵阴性的个体。
我们的数据表明，POC-CCA 试验作为曼氏血吸虫感染诊断的辅助工具具有一定潜力，比从三个不同粪便样本中获得的 16 张加藤厚涂片结果更好。然而，免疫层析试验在验证治疗后的治愈率方面缺乏足够的特异性和灵敏度。
