Foundation for Innovative New Diagnostics, Uganda Ministry of Health, Kampala, Uganda.
J Infect Dis. 2013 Aug 15;208(4):645-52. doi: 10.1093/infdis/jit184. Epub 2013 Apr 30.
Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. Molecular methods such as polymerase chain reaction (PCR) are highly sensitive but remain too complex for field deployment. A new commercial molecular assay based on loop-mediated isothermal amplification (LAMP) was assessed for field use.
Malaria LAMP (Eiken Chemical, Japan) was evaluated for samples from 272 outpatients at a rural Ugandan clinic and compared with expert microscopy, nested PCR, and quantitative PCR (qPCR). Two technicians performed the assay after 3 days of training, using 2 alternative blood sample-preparation methods and visual interpretation of results by fluorescence assay.
Compared with 3-well nested PCR, the sensitivity of both LAMP and single-well nested PCR was 90%; the microscopy sensitivity was 51%. For samples with a Plasmodium falciparum qPCR titer of ≥ 2 parasites/µL, LAMP sensitivity was 97.8% (95% confidence interval, 93.7%-99.5%). Most false-negative LAMP results involved samples with parasitemia levels detectable by 3-well nested PCR but very low or undetectable by qPCR.
Malaria LAMP in a remote Ugandan clinic achieved sensitivity similar to that of single-well nested PCR in a United Kingdom reference laboratory. LAMP dramatically lowers the detection threshold achievable in malaria-endemic settings, providing a new tool for diagnosis, surveillance, and screening in elimination strategies.
当前的疟疾诊断检测方法，包括显微镜检查和抗原检测快速检测，无法可靠地检测低密度感染。聚合酶链反应（PCR）等分子方法具有很高的敏感性，但仍然过于复杂，无法在现场部署。一种新的基于环介导等温扩增（LAMP）的商业分子检测方法已被评估用于现场使用。
疟疾 LAMP（日本荣研化学）对 272 名乌干达农村诊所的门诊患者样本进行了评估，并与专家显微镜检查、巢式 PCR 和定量 PCR（qPCR）进行了比较。两名技术人员在接受 3 天培训后使用两种替代的血液样本制备方法和荧光测定法对结果进行目视解释来进行检测。
与 3 孔巢式 PCR 相比，LAMP 和单孔巢式 PCR 的灵敏度均为 90%；显微镜检查的灵敏度为 51%。对于 Plasmodium falciparum qPCR 滴度≥2 个寄生虫/µL 的样本，LAMP 的灵敏度为 97.8%（95%置信区间，93.7%-99.5%）。大多数假阴性 LAMP 结果涉及到通过 3 孔巢式 PCR 可检测到寄生虫血症水平但通过 qPCR 检测非常低或无法检测到的样本。
在乌干达偏远诊所进行的疟疾 LAMP 检测达到了英国参考实验室中单孔巢式 PCR 的敏感性。LAMP 极大地降低了在疟疾流行地区可实现的检测阈值，为诊断、监测和筛查消除策略提供了新的工具。
