Performance of microscopy and RDTs in the context of a malaria prevalence survey in Angola: a comparison using PCR as the gold standard
Performance of microscopy and RDTs in the context of a malaria prevalence survey in Angola: a comparison using PCR as the gold standard
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DOI：
10.1186/1475-2875-12-284
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发表时间：
2013-08-13
期刊：
影响因子：
3
通讯作者：
Nery, Susana V.
中科院分区：
文献类型：
--
作者：
Fancony, Claudia;Sebastiao, Yuri V.;Nery, Susana V.
背景：在社区调查中准确识别疟原虫感染对成功控制疟疾至关重要。显微镜检查和快速诊断测试是在实地调查中诊断疟疾的主要技术。虽然显微镜仍然被认为是黄金标准，但RDT越来越受欢迎，因为它们允许快速和廉价的诊断。作者利用2010年在安哥拉西北部进行的一项流行率调查的数据，以聚合酶链反应（PCR）为金标准，旨在比较显微镜和RDT在鉴别恶性疟原虫感染方面的性能。方法：3，307名受试者的结果（1 225名学龄前儿童（0至5奥尔兹，1 134名学龄儿童）（6至15奥尔兹）和948名母亲/照顾者（>15岁））进行恶性疟原虫感染测试。采用McNemar's检验和配对数据的加权广义评分卡方检验比较显微镜和Paracheck-Pf（R）的敏感性、特异性、阳性预测值和阴性预测值（PPV和NPV）。与显微镜相比，Paracheck-Pf（R）具有显著更高的灵敏度（72.8%对60%），特异性（94.3%对92.5%），PPV（70.7%对60%）和NPV（94.8%对92.5%）。这两种测试在母亲中的敏感性明显较低（显微镜检查为36.8%，Paracheck-Pf（R）为43.7%）（0至5岁的显微镜检查率为68.4%，6至15岁的显微镜检查率为60.6%; 0至5岁的Paracheck-Pf（R）为80.4%，6至15岁的Paracheck-Pf（R）为76.5%）。与PCR相比，显微镜检查和RDT均表现不佳。假阴性可能与样本的低寄生虫密度特征相关。假阳性可能与这些技术的充分描述的局限性有关，例如显微镜专家的专业水平或RDT病例中既往感染的持续抗原性。尽管如此，RDT在检测疟疾感染方面的性能比显微镜更高，有利于在社区横断面疟疾调查中使用RDT，而在社区横断面疟疾调查中，显微镜的专业性能很难实现。
Background: Accurate identification of Plasmodium infections in community surveys is essential to successful malaria control. Microscopy and rapid diagnostic tests (RDTs) are the main techniques used to diagnose malaria in field-based surveys. While microscopy is still considered the gold standard, RDTs are growing in popularity as they allow for rapid and inexpensive diagnosis. Using data from a prevalence survey conducted in north-western Angola in 2010, the authors aimed to compare the performance of microscopy and RDTs in identifying Plasmodium falciparum infections, using polymerase chain reaction (PCR) as the gold standard.Methods: Results from 3,307 subjects (1,225 preschool-aged children (zero to five year olds), 1,134 school-aged children (six to 15 year olds) and 948 mothers/caregivers (>15 years of age)), tested for P. falciparum infections, were utilized. The sensitivity, specificity, positive, and negative predictive values (PPV and NPV) of microscopy and Paracheck-Pf (R) were compared using the McNemar's test and the weighted generalized score Chi-squared test for paired data.Results: The prevalence of P. falciparum infections determined by PCR and microscopy was 15.9% and by Paracheck-Pf (R) was 16.3%. Compared to microscopy, Paracheck-Pf (R) had significantly higher sensitivity (72.8% versus 60%), specificity (94.3% versus 92.5%), PPV (70.7% versus 60%) and NPV (94.8% versus 92.5%). Both tests had significantly lower sensitivity in mothers (36.8% for microscopy and 43.7% for Paracheck-Pf (R)) than in their children (68.4% in zero to five years-old and 60.6% in six to 15 years-old for microscopy and 80.4% in zero to five year-olds and 76.5% in six to 15 year-olds for Paracheck-Pf (R)).Conclusion: Both microscopy and RDTs performed suboptimally when compared to PCR. False negativity could be associated with the low parasite density profile of the samples. False positivity may be related to the well-described limitations of those techniques such as level of expertise of microscopists or persistent antigenicity from previous infections in the case of RDTs. Nevertheless, RDTs had enhanced performance comparatively to microscopy in detecting malaria infections, favouring their use in community cross-sectional malaria surveys, where expert performance of microscopy is hard to accomplish.