Mwanza Medical Research Center, National Institute for Medical Research, Mwanza, Tanzania.
National Institute of Medical Research, Head Quarters, P.O. Box 9653, Dar es Salaam, Tanzania.
Malar J. 2021 Jan 22;20(1):58. doi: 10.1186/s12936-020-03568-z.
Precise detection of Plasmodium infections in community surveys is essential for effective malaria control. Microscopy and rapid diagnostic tests (RDTs) are the major techniques used to identify malaria infections in the field-based surveys. Although microscopy is still considered as the gold standard, RDTs are increasingly becoming versatile due to their rapid and adequate performance characteristics.
A malaria prevalence cross-sectional survey was carried out in north-western Tanzania in 2016, aimed at appraising the performance of high sensitivity Plasmodium falciparum (HSPf) tests compared to SD Bioline Pf and microscopy in detecting P. falciparum infections. A total of 397 individuals aged five years and above were tested for P. falciparum infections. The sensitivity, specificity, positive, and negative predictive values (PPV and NPV) of microscopy, Pf RDT and HSPf RDT was determined using PCR as the gold standard method.
The prevalence of P. falciparum infections determined by microscopy, SD Bioline Pf, HSPf and PCR was 21.9, 27.7, 33.3 and 43.2%, respectively. The new HSPf RDT had significantly higher sensitivity (98.2%) and specificity (91.6%) compared to the routinely used SD Bioline Pf RDT(P < 0.001). The positive predictive value (PPV) was 81.8% and the negative predictive value (NPV) was 99.2% for the routinely used SD Bioline Pf RDT. Moreover, HSPf RDT had sensitivity of 69% and specificity of 76.8% compared to microscopy. The PPV was 45.5% and the NPV was 89.8% for microscopy. Furthermore, the analytical sensitivity test indicated that the newly developed HSPf RDT had lower detection limits compared to routinely used SD Bioline RDT.
HSPf RDT had better performance when compared to both microscopy and the currently used malaria RDTs. The false negativity could be associated with the low parasite density of the samples. False positivity may be related to the limitations of the expertise of microscopists or persistent antigenicity from previous infections in the case of RDTs. Nevertheless, HS PfRDT performed better compared to routinely used Pf RDT, and microscopy in detecting malaria infections. Therefore, HS Pf RDT presents the best alternative to the existing commercial/regularly available RDTs due to its sensitivity and specificity, and reliability in diagnosing malaria infections.
在社区调查中准确检测疟原虫感染对于有效控制疟疾至关重要。显微镜检查和快速诊断检测（RDT）是用于现场调查中识别疟疾感染的主要技术。尽管显微镜检查仍然被认为是金标准，但由于其快速和足够的性能特点，RDT 越来越多样化。
2016 年在坦桑尼亚西北部进行了一项疟疾患病率横断面调查，旨在评估高灵敏度恶性疟原虫（HSPf）检测与 SD Bioline Pf 和显微镜检查在检测恶性疟原虫感染方面的性能。共有 397 名五岁及以上的个体接受了恶性疟原虫感染检测。使用 PCR 作为金标准方法，确定了显微镜检查、Pf RDT 和 HSPf RDT 的灵敏度、特异性、阳性和阴性预测值（PPV 和 NPV）。
显微镜检查、SD Bioline Pf、HSPf 和 PCR 确定的恶性疟原虫感染患病率分别为 21.9%、27.7%、33.3%和 43.2%。新的 HSPf RDT 的灵敏度（98.2%）和特异性（91.6%）明显高于常规使用的 SD Bioline Pf RDT（P<0.001）。常规使用的 SD Bioline Pf RDT 的阳性预测值（PPV）为 81.8%，阴性预测值（NPV）为 99.2%。此外，HSPf RDT 与显微镜检查相比，灵敏度为 69%，特异性为 76.8%。PPV 为 45.5%，NPV 为 89.8%。此外，分析灵敏度测试表明，新开发的 HSPf RDT 的检测下限低于常规使用的 SD Bioline RDT。
HSPf RDT 的性能优于显微镜检查和目前使用的疟疾 RDT。假阴性可能与样本中寄生虫密度低有关。假阳性可能与显微镜专家的专业知识限制或 RDT 中先前感染的持续抗原性有关。然而，HS PfRDT 在检测疟疾感染方面的表现优于常规使用的 Pf RDT 和显微镜检查。因此，由于其灵敏度、特异性和诊断疟疾感染的可靠性，HS Pf RDT 是现有商业/常规 RDT 的最佳替代品。
