Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.
Research Unit of Clinical Microbiology, Department of Clinical Research, Faculty of Health Science, University of Southern Denmark, Odense, Denmark.
Am J Trop Med Hyg. 2019 Mar;100(3):566-571. doi: 10.4269/ajtmh.18-0496.
Malaria is traditionally diagnosed by blood smear microscopy, which requires continuous resource-demanding training. In areas with only a few cases of malaria, a simple and rapid test that can reliably exclude malaria could significantly reduce the need for microscopy and training. We evaluated whether loop-mediated isothermal amplification (LAMP) for screening malaria parasites could reduce the workload in the diagnosis of malaria. Loop-mediated isothermal amplification was used to analyze 38 ethylene-diamine-tetraacetic acid (EDTA) blood samples from 23 patients who had previously been tested for malaria by microscopy, antigen-based rapid diagnostic test (antigen-RDT), and in-house real-time polymerase chain reaction (RT-PCR). The samples included blood with low-level parasitaemia and samples with discrepancies between the results of the different methods. Loop-mediated isothermal amplification detected malaria parasites in 27 of 28 samples that were positive according to in-house RT-PCR. There were negative microscopy results in 10 of these and negative antigen-RDT results in 11. The sample with a negative LAMP result and positive in-house RT-PCR result was from a patient who had recently been treated for low-level malaria parasitaemia. We found LAMP to be reliable for malaria screening and suitable for replacing microscopy without loss of performance. The low number of LAMP-positive samples needing microscopy can be handled by a limited number of trained microscopists. The time saved on training and documentation was estimated to be 520 working hours yearly in our laboratory. Using LAMP for primary screening of patient samples, we have made a diagnostic workflow that ensures more reliable, faster, and less resource-demanding diagnosis of malaria.
疟疾传统上通过血涂片显微镜检查进行诊断，这需要持续的资源密集型培训。在疟疾病例较少的地区，一种简单、快速且可靠排除疟疾的检测方法可以显著减少对显微镜检查和培训的需求。我们评估了环介导等温扩增（LAMP）用于筛查疟原虫是否可以减少疟疾诊断的工作量。使用环介导等温扩增分析了 38 份乙二胺四乙酸（EDTA）血液样本，这些样本来自 23 名先前通过显微镜检查、抗原快速诊断检测（抗原-RDT）和内部实时聚合酶链反应（RT-PCR）检测过疟疾的患者。这些样本包括低水平寄生虫血症的血液样本和不同方法结果不一致的样本。环介导等温扩增检测到 28 份根据内部 RT-PCR 结果为阳性的样本中的疟原虫。其中 10 份显微镜检查结果为阴性，11 份抗原-RDT 结果为阴性。LAMP 结果为阴性而内部 RT-PCR 结果为阳性的样本来自一位最近因低水平疟疾寄生虫血症接受治疗的患者。我们发现 LAMP 可靠用于疟疾筛查，并且在不影响性能的情况下适合替代显微镜检查。需要显微镜检查的 LAMP 阳性样本数量较少，可以由少数经过培训的显微镜检查人员处理。在我们的实验室中，每年通过培训和文件处理节省的时间估计为 520 个工作小时。通过使用 LAMP 对患者样本进行初步筛查，我们建立了一个诊断工作流程，确保疟疾的诊断更加可靠、快速且资源需求较低。
