Department of Medical Microbiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
Laboratory for Medical Microbiology and Immunology, Meander Medical Center, Amersfoort, The Netherlands.
Eur J Clin Microbiol Infect Dis. 2018 Dec;37(12):2323-2329. doi: 10.1007/s10096-018-3378-4. Epub 2018 Sep 26.
Almost a decade ago our diagnostic laboratory implemented an in-house real-time PCR for the detection of Plasmodium DNA to diagnose malaria in parallel with conventional diagnostics, i.e., microscopy (thick and thin smears), quantitative buffy coat microscopy (QBC), and a rapid diagnostic test (RDT). Here we report our experiences and make a comparison between the different diagnostic procedures used in this non-endemic setting. All patients during the period February 2009-December 2017 suspected of malaria were prospectively tested at the moment of sample collection. Both PCR and conventional malaria diagnostics were carried out on a total of 839 specimens from 825 patients. In addition, three Plasmodium falciparum (Pf) patients were closely followed by real-time PCR and microscopy after treatment. Overall, 56 samples (55 patients) tested positive by real-time PCR, of which six were missed by microscopy and seven by QBC. RDT showed fairly good results in detecting Pf, whereas specificity was not optimal. RDT failed to detect 10 of 17 non-Pf PCR positive specimens. One Plasmodium malariae patient would have been missed if only conventional diagnostic tests had been used. The high sensitivity of the PCR was confirmed by the number of PCR positive, microscopy negative post-treatment samples. In conclusion, within our routine diagnostic setting, malaria real-time PCR not only showed a high level of agreement with the conventional methods used, but also showed higher sensitivity and better specificity. Still, for complete replacement of the conventional procedures in a non-endemic setting, the time-to-results of the real-time PCR is currently too long.
大约十年前,我们的诊断实验室实施了一种内部实时 PCR 方法,用于检测疟原虫 DNA,以与传统诊断方法(即显微镜检查[厚涂片和薄涂片]、定量血涂片显微镜检查[QBC]和快速诊断测试[RDT])并行诊断疟疾。在这里,我们报告我们的经验,并比较在这种非流行地区使用的不同诊断程序。在 2009 年 2 月至 2017 年 12 月期间,所有疑似疟疾的患者在采集样本时都进行了前瞻性检测。总共对 825 名患者的 839 份标本进行了 PCR 和常规疟疾诊断。此外,对 3 名恶性疟原虫(Pf)患者进行了实时 PCR 和显微镜检查密切随访。总体而言,56 份(55 名患者)样本实时 PCR 检测呈阳性,其中 6 份被显微镜检查漏检,7 份被 QBC 漏检。RDT 在检测 Pf 方面表现出相当好的结果,但其特异性并不理想。RDT 未能检测到 17 份非 Pf PCR 阳性标本中的 10 份。如果仅使用常规诊断测试,就会错过 1 例间日疟原虫患者。PCR 阳性、显微镜检查阴性的治疗后样本数量证实了 PCR 的高灵敏度。总之,在我们的常规诊断环境中,疟疾实时 PCR 不仅与使用的常规方法具有高度一致性,而且还具有更高的灵敏度和更好的特异性。然而,对于在非流行地区完全替代常规程序,实时 PCR 的结果时间目前还太长。