BACKGROUND There is significant need for accurate diagnostic tools for Cryptosporidium spp. and Giardia duodenalis infections in resource limited countries where diarrhoeal disease caused by these parasites is often prevalent. The present study assessed the diagnostic performance of three commercially available rapid diagnostic tests (RDTs) based on faecal-antigen detection for Cryptosporidium spp. and/or G. duodenalis infections in stool samples of children admitted with severe acute malnutrition (SAM) and diarrhoea. An established multiplex PCR was used as reference test. METHODS Stool samples from children with SAM and diarrhoea enrolled in a randomized controlled trial (registered at clinicaltrials.gov/ct2/show/NCT02246296) in Malawi (n = 175) and Kenya (n = 120) between December 2014 and December 2015 were analysed by a multiplex PCR for the presence of Cryptosporidium spp., G. duodenalis or Entamoeba histolytica parasite DNA. Cryptosporidium-positive samples were species typed using restriction fragment length polymorphism analysis. A sub-sample of the stool specimens (n = 236) was used for testing with three different RDTs. Diagnostic accuracy of the tests under evaluation was assessed using the results of PCR as reference standard using MedCalc software. Pearson Chi-square test and Fisher's exact test were used to determine (significant) difference between the number of cryptosporidiosis or giardiasis cases found by PCR in Malawi and Kenya. The overall diagnostic accuracy of each RDT was calculated by plotting a receiver operating characteristic (ROC) curve for each test and to determine the area under the curve (AUC) using SPSS8 software. RESULTS Prevalence of Cryptosporidium spp. by PCR was 20.0 and 21.7% in Malawi and Kenya respectively, mostly C. hominis. G. duodenalis prevalence was 23.4 and 5.8% in Malawi and Kenya respectively. E. histolytica was not detected by PCR. RDT testing followed the same pattern of prevalence. RDT sensitivities ranged for cryptosporidiosis from 42.9 to 76.9% and for G. duodenalis from 48.2 to 85.7%. RDT specificities ranged from 88.4 to 100% for Cryptosporidium spp. and from 91.2 to 99.2% for G. duodenalis infections. Based on the estimated area under the curve (AUC) values, all tests under evaluation had an acceptable overall diagnostic accuracy (> 0.7), with the exception of one RDT for Cryptosporidium spp. in Malawi. CONCLUSIONS All three RDTs for Cryptosporidium spp. and Giardia duodenalis evaluated in this study have a moderate sensitivity, but sufficient specificity. The main value of the RDTs is within their rapidness and their usefulness as screening assays in surveys for diarrhoea.

中文翻译：

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执行三种快速诊断测试以检测隐孢子虫的能力。严重急性营养不良和腹泻的儿童中的十二指肠和十二指肠（Giardia duodenalis）。

背景技术非常需要用于隐孢子虫的精确诊断工具。在资源有限的国家（通常由这些寄生虫引起的腹泻疾病），感染十二指肠和贾第鞭毛虫。本研究基于对粪隐孢子虫的粪便抗原检测，评估了三种市售快速诊断测试（RDT）的诊断性能。和/或患有严重急性营养不良（SAM）和腹泻的儿童粪便样本中的十二指肠球菌（G. duodenalis）感染。建立的多重PCR用作参考测试。方法从SAM和腹泻患儿的粪便样本中进行一项随机对照试验（在临床试验中进行注册）。通过多重PCR分析了2014年12月至2015年12月在马拉维（n = 175）和肯尼亚（n = 120）的gov / ct2 / show / NCT02246296）隐孢子虫，十二指肠球菌或溶组织变形杆菌DNA的存在。使用限制性片段长度多态性分析对隐孢子虫阳性样品进行分型。粪便样本的子样本（n = 236）用于测试三种不同的RDT。使用MedCalc软件，以PCR结果为参考标准，评估了评估测试的诊断准确性。使用Pearson卡方检验和Fisher精确检验来确定通过PCR在马拉维和肯尼亚发现的隐孢子虫病或贾第鞭毛虫病病例数之间的（显着）差异。通过绘制每个测试的接收器工作特性（ROC）曲线并使用SPSS8软件确定曲线下的面积（AUC），可以计算出每个RDT的总体诊断准确性。结果隐孢子虫的患病率。通过PCR的结果在马拉维和肯尼亚分别为20.0和21.7％，主要是人参衣原体。马拉维和肯尼亚的十二指肠球菌患病率分别为23.4和5.8％。PCR未检测到溶组织性大肠杆菌。RDT测试遵循相同的患病率模式。隐孢子虫病的RDT敏感性为42.9％至76.9％，十二指肠球菌的RDT敏感性为48.2％至85.7％。隐孢子虫的RDT特异性范围为88.4至100％。十二指肠杆菌的感染率从91.2％降至99.2％。根据曲线下的估算面积（AUC）值，评估的所有测试的总体诊断准确度均可接受（> 0.7），除了隐孢子虫的一种RDT。在马拉维。结论隐孢子虫的所有三种RDTs。在这项研究中评估的十二指肠和十二指肠具有中等敏感性，但具有足够的特异性。RDT的主要价值在于其快速性及其在腹泻调查中作为筛选测定的有用性。