OBJECTIVES Malaria is one of most common tropical diseases encountered in travellers and migrants. It requires an urgent and reliable diagnosis considering its potential severity. In this study, performance of five diagnostic assays were evaluated in a nonendemic region and compared prospectively to quantitative PCR (qPCR). METHODS A prospective study was conducted at Toulouse Hospital from August 2017 to January 2018 and included all patients with initial Plasmodium screening. Thin and thick blood smears (TnS, TkS), quantitative buffy coat (QBC), rapid diagnostic tests (RDTs) and commercial loop-mediated isothermal amplification (LAMP) were independently performed on each blood sample and compared to our qPCR reference standard. RESULTS The study encompassed 331 patients, mainly returning from Africa. qPCR detected 73 Plasmodium-positive samples (including 58 falciparum). Individually, LAMP had a 97.3% (71/73) sensitivity, far ahead of TnS (84.9%, 62/73), TkS (86.3%, 63/73), QBC (86.3%, 63/73) and RDT (86.3%, 63/73). RDT demonstrated a high sensitivity for falciparum (98.3%, 57/58) but missed all ovale, malariae and knowlesi infections. Specificity was excellent for all techniques (99.6-100%). The most sensitive diagnosis strategies were TnS + RDT (95.9%, 70/73), TnS + LAMP (97.3%, 71/73) and TnS + RDT + LAMP (100%, 73/73), about 10% higher than strategies using exclusively microscopy, TkS + TnS (87.7%, 64/73) or QBC + TnS (87.7%, 64/73). TnS remains necessary for Plasmodium species identification and quantification. Adding sequentially TnS only on LAMP-positive samples did not decrease TnS + LAMP strategy sensitivity. CONCLUSIONS In nonendemic countries, the currently recommended microscopy-based strategies seem unsatisfactory for malaria diagnosis considering RDT and LAMP performance, two rapid and sensitive assays that require limited training.

中文翻译：

---

基于显微镜技术，快速诊断测试和分子环介导的等温扩增法对进口疟疾进行诊断的不同策略的性能评估。

目标疟疾是旅行者和移民中遇到的最常见的热带疾病之一。考虑到其潜在的严重性，它需要紧急而可靠的诊断。在这项研究中，在非流行地区评估了五种诊断测定的性能，并将其与定量PCR（qPCR）进行了前瞻性比较。方法于2017年8月至2018年1月在图卢兹医院进行了一项前瞻性研究，纳入了所有接受初次疟原虫筛查的患者。分别对每个血液样本进行了稀薄和厚薄的血液涂片（TnS，TkS），定量血沉棕黄层（QBC），快速诊断测试（RDT）和商业定量环介导的等温扩增（LAMP），并与我们的qPCR参考标准进行了比较。结果该研究包括331名患者，主要来自非洲。qPCR检测到73个疟原虫阳性样品（包括58个恶性疟原虫）。LAMP的敏感性分别为97.3％（71/73），远远高于TnS（84.9％，62/73），TkS（86.3％，63/73），QBC（86.3％，63/73）和RDT（86.3） ％，63/73）。RDT对恶性疟具有很高的敏感性（98.3％，57/58），但错过了所有卵圆形，疟疾和诺氏菌感染。所有技术的特异性均极佳（99.6-100％）。最敏感的诊断策略是TnS + RDT（95.9％，70/73），TnS + LAMP（97.3％，71/73）和TnS + RDT + LAMP（100％，73/73），比策略高约10％使用独家显微镜，TkS + TnS（87.7％，64/73）或QBC + TnS（87.7％，64/73）。TnS仍然是疟原虫物种鉴定和定量所必需的。仅在LAMP阳性样品上顺序添加TnS不会降低TnS + LAMP策略的敏感性。