BACKGROUND Malaria diagnostics by rapid diagnostic test (RDT) relies primarily on the qualitative detection of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) and Plasmodium spp lactate dehydrogenase (pLDH). As novel RDTs with increased sensitivity are being developed and implemented as point of care diagnostics, highly sensitive laboratory-based assays are needed for evaluating RDT performance. Here, a quantitative suspension array technology (qSAT) was developed, validated and applied for the simultaneous detection of PfHRP2 and pLDH in a variety of biological samples (whole blood, plasma and dried blood spots) from individuals living in different endemic countries. RESULTS The qSAT was specific for the target antigens, with analytical ranges of 6.8 to 762.8 pg/ml for PfHRP2 and 78.1 to 17076.6 pg/ml for P. falciparum LDH (Pf-LDH). The assay detected Plasmodium vivax LDH (Pv-LDH) at a lower sensitivity than Pf-LDH (analytical range of 1093.20 to 187288.5 pg/ml). Both PfHRP2 and pLDH levels determined using the qSAT showed to positively correlate with parasite densities determined by quantitative PCR (Spearman r = 0.59 and 0.75, respectively) as well as microscopy (Spearman r = 0.40 and 0.75, respectively), suggesting the assay to be a good predictor of parasite density. CONCLUSION This immunoassay can be used as a reference test for the detection and quantification of PfHRP2 and pLDH, and could serve for external validation of RDT performance, to determine antigen persistence after parasite clearance, as well as a complementary tool to assess malaria burden in endemic settings.

中文翻译：

---

通过定量悬浮阵列技术在全血，干血斑和血浆中对疟疾抗原PfHRP2和pLDH进行定量。

背景技术通过快速诊断测试（RDT）进行的疟疾诊断主要依靠定性检测恶性疟原虫组氨酸富集蛋白2（PfHRP2）和恶性疟原虫乳酸脱氢酶（pLDH）。随着灵敏度更高的新型RDT的开发和实现作为护理点诊断，需要高度敏感的基于实验室的测定法来评估RDT性能。在这里，定量悬浮阵列技术（qSAT）被开发，验证并应用于同时检测来自不同流行国家的个体的各种生物样品（全血，血浆和干血斑）中的PfHRP2和pLDH。结果qSAT对靶抗原具有特异性，PfHRP2的分析范围为6.8至762.8 pg / ml，恶性疟原虫LDH（Pf-LDH）的分析范围为78.1至17076.6 pg / ml。该测定法检测到间日疟原虫LDH（Pv-LDH）的灵敏度低于Pf-LDH（分析范围1093.20至187288.5 pg / ml）。使用qSAT测定的PfHRP2和pLDH水平均与通过定量PCR（分别为Spearman r = 0.59和0.75）和显微镜检查（Spearman r = 0.40和0.75）测定的寄生虫密度呈正相关。寄生虫密度的良好预测指标。结论该免疫分析法可作为检测和定量PfHRP2和pLDH的参考试验，并可用于RDT性能的外部验证，确定寄生虫清除后的抗原持久性，以及评估地方病疟疾负担的辅助工具。设置。