Molecular malaria diagnostics: A systematic review and meta-analysis

Accurate diagnosis of malaria is essential for identification and subsequent treatment of the disease. Currently, microscopy and rapid diagnostic tests are the most commonly used diagnostics, next to treatment based on clinical signs only. These tests are easy to deploy, but have a relatively high detection limit. With declining prevalence in many areas, there is an increasing need for more sensitive diagnostics. Molecular tools may be a suitable alternative, although costs and technical requirements currently hamper their implementation in resource limited settings. A range of (near) point-of-care diagnostics is therefore under development, including simplifications in sample preparation, amplification and/or read-out of the test. Accuracy data, in combination with technical characteristics, are essential in determining which molecular test, if any, would be the most promising to be deployed. This review presents a comprehensive overview of the currently available molecular malaria diagnostics, ranging from well-known tests to platforms in early stages of evaluation, and systematically evaluates their published accuracy. No important difference in accuracy was found between the most commonly used PCR-based assays (conventional, nested and real-time PCR), with most of them having high sensitivity and specificity, implying that there are no reasons other than practical ones to choose one technique over the other. Loop-mediated isothermal amplification and other (novel) diagnostics appear to be highly accurate as well, with some offering potential to be used in resource-limited settings.

准确诊断疟疾对于该病的识别与后续治疗至关重要。当前，除仅依据临床体征开展治疗外，显微镜检查与快速诊断测试（rapid diagnostic tests）是最常用的诊断手段。此类方法部署便捷，但检测限相对偏高。随着诸多地区疟疾患病率不断降低，对灵敏度更优的诊断技术的需求愈发迫切。分子诊断工具或为理想替代方案，但目前成本与技术要求制约了其在资源匮乏地区的推广应用。为此，一系列（近乎）即时诊断（point-of-care）技术正处于研发阶段，其中涵盖样本制备、扩增及/或检测判读流程的简化方案。诊断准确性数据结合技术特性，是筛选最具推广潜力的分子检测手段（若存在此类手段）的核心依据。本综述全面梳理了当前已有的疟疾分子诊断技术，覆盖成熟检测方法与处于早期评估阶段的平台，并系统评估了已发表的准确性相关数据。研究显示，最常用的基于聚合酶链式反应（PCR）的检测方法（普通PCR、巢式PCR与实时荧光定量PCR）在准确性上无显著差异，多数此类方法均具备较高的灵敏度与特异性，这意味着除实操层面的考量外，并无其他理由在不同技术间做出优先选择。环介导等温扩增（loop-mediated isothermal amplification, LAMP）及其他新型诊断技术同样展现出优异的准确性，其中部分技术具备在资源匮乏场景中推广应用的潜力。