Department of Clinical Laboratory Sciences, Al-Ghad International College for Applied Medical Sciences, Dammam, Saudi Arabia (KSA); Department of Medical Parasitology, Faculty of Medical Laboratory Sciences, University of Gezira, Sudan.
Department of Biochemistry and Nutrition, Faculty of Medicine, University of Gezira, Sudan; Department of Basic Medical Sciences, Faculty of Applied Medical Sciences, Al Baha University, KSA.
Acta Trop. 2020 Nov;211:105599. doi: 10.1016/j.actatropica.2020.105599. Epub 2020 Jun 25.
Visceral Leishmaniasis (VL), a life-threating disease in Sudan and Eastern Africa, is usually diagnosed by a painful and invasive tissue aspirate microscopy. This study assessed the diagnostic effectiveness of buffy coat (BC) microscopy and the rK39 immunoassay test separately and combined as an easy non-invasive method applied to peripheral blood sample for field diagnosis of VL. 151 VL suspected patients were recruited from tertiary rural hospitals in Bazura, Gedaref state, from 2014-2015. All patients were tested for VL using rK39 ICT and microscopy smears from LN aspirate and BC in addition to PCR from BC as a reference standard test. Both BC and LN aspirate microscopy showed perfect specificity (100%) with false negative results, while the majority of true positives (81%) had a low-parasite burden. ICT showed almost perfect agreement but limited by its poor specificity. Each of these three tests is inadequate as a consistent single diagnostic tool and should be replaced by PCR in routine practice. Combining the results of risk-free BC microscopy and rk39 ICT, using peripheral blood sample, improved VL diagnosis with almost perfect agreement and 93.4% accuracy. Our findings indicate that combined BC microscopy and ICT are accurate, simple and easy point-of-care VL diagnostic tools in community and rural hospitals that can replace or reduce the use of invasive tissue aspirates microscopy, when PCR is unavailable. This is particularly of value in endemic rural areas, decreasing the delay in final diagnosis and preventing deaths caused by VL.
内脏利什曼病（VL）是苏丹和东非地区危及生命的疾病，通常通过痛苦且具侵入性的组织抽吸显微镜检查进行诊断。本研究评估了血涂片（BC）显微镜检查和 rK39 免疫测定试验单独和联合作为一种简单的非侵入性方法应用于外周血样本，用于现场诊断 VL。2014-2015 年，从巴祖拉的三级农村医院招募了 151 名 VL 疑似患者。所有患者均使用 rK39 ICT 和 LN 抽吸及 BC 涂片进行 VL 检测，并对 BC 进行 PCR 检测作为参考标准检测。BC 和 LN 抽吸显微镜检查均具有完美的特异性（100%），假阴性结果，而大多数真阳性（81%）的寄生虫载量较低。ICT 显示出几乎完美的一致性，但特异性较差。这三种测试中的每一种都不足以作为一种一致的单一诊断工具，应在常规实践中被 PCR 取代。结合风险较低的 BC 显微镜检查和 rk39 ICT 的结果，使用外周血样本，几乎完美的一致性和 93.4%的准确性提高了 VL 诊断。我们的研究结果表明，联合 BC 显微镜检查和 ICT 是准确、简单且易于在社区和农村医院进行的 VL 诊断工具，可替代或减少对侵入性组织抽吸显微镜检查的使用，尤其是在 PCR 不可用时。这在流行地区尤其有价值，可以减少最终诊断的延迟，并防止因 VL 导致的死亡。
