Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana.
West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana.
Malar J. 2021 Mar 2;20(1):125. doi: 10.1186/s12936-021-03665-7.
The Alere™ Malaria Ag P.f Ultra-sensitive RDT (UsmRDT) kit is an HRP2-based malaria rapid diagnostic test (RDT) with enhanced sensitivity relative to the SD Bioline Malaria Ag P.f RDT (mRDT) kit. However, the diagnostic performance of the UsmRDT kit has not been evaluated in Ghana.
A total of 740 afebrile participants aged between 3 and 88 years old were recruited from the Central and Greater Accra Regions of Ghana during the off-peak malaria season. Axillary body temperature was measured, and a volume of 1 ml venous blood was drawn from each participant. Prior to separating the blood into plasma and packed cell pellets via centrifugation, the blood was spotted onto one UsmRDT and one mRDT kit and also used to prepare thick and thin blood smears as well as filter paper blood spots. Plasmodium falciparum specific polymerase chain reaction (PCR) was performed on gDNA extracted from 100 µl of the whole blood.
The overall positivity rate for microscopy, PCR, UsmRDT and mRDT kit were 20.4%, 40.8%, 31.3% and 30.8%, respectively. Overall, the UsmRDT identified 9.3% (28/302) more PCR positive samples than the mRDT kits. All samples that were negative by the UsmRDT kit were also negative by the mRDT kit. Overall, the sensitivity and specificity of the UsmRDT was 73% (221/302) and 89% (388/436), respectively, while that for the mRDT kit was 58% and 90%, respectively.
Although the UsmRDT kit was not as sensitive as PCR at detecting asymptomatic P. falciparum carriage, it correctly identified P. falciparum in 9.3% of the study participants that were not captured by the mRDT kit. In malaria endemic settings, the UsmRDT would provide an added advantage by identifying more asymptomatic P. falciparum carriers than the mRDT kit for targeted treatment interventions.
Alere™ Malaria Ag P.f Ultra-sensitive RDT（UsmRDT）试剂盒是一种基于 HRP2 的疟疾快速诊断检测试剂盒（RDT），与 SD Bioline Malaria Ag P.f RDT（mRDT）试剂盒相比，其灵敏度有所提高。然而，该试剂盒在加纳的诊断性能尚未得到评估。
在疟疾非高峰期，从加纳中部和大阿克拉地区招募了 740 名年龄在 3 至 88 岁之间的无热参与者。测量腋温，并从每个参与者中抽取 1 毫升静脉血。在将血液通过离心分离为血浆和红细胞压积之前，将血液点样到一个 UsmRDT 和一个 mRDT 试剂盒上，并用于制备厚血涂片和薄血涂片以及滤纸血斑。从 100μl 全血中提取 gDNA 后，进行疟原虫特异性聚合酶链反应（PCR）。
显微镜检查、PCR、UsmRDT 和 mRDT 试剂盒的总阳性率分别为 20.4%、40.8%、31.3%和 30.8%。总体而言，UsmRDT 比 mRDT 试剂盒多检出 9.3%（28/302）的 PCR 阳性样本。所有通过 UsmRDT 试剂盒检测为阴性的样本也通过 mRDT 试剂盒检测为阴性。总体而言，UsmRDT 的灵敏度和特异性分别为 73%（221/302）和 89%（388/436），而 mRDT 试剂盒的灵敏度和特异性分别为 58%和 90%。
虽然 UsmRDT 试剂盒在检测无症状疟原虫携带方面不如 PCR 敏感，但它正确识别了 mRDT 试剂盒未捕捉到的 9.3%的研究参与者中的疟原虫。在疟疾流行地区，UsmRDT 试剂盒通过比 mRDT 试剂盒识别更多的无症状疟原虫携带者，为有针对性的治疗干预提供了额外的优势。
