Infectious Diseases Institute, Makerere University College of Health Sciences, P.O. Box, 7072, Kampala, Uganda.
Department of Medicine, School of Medicine, Makerere University College of Heath Sciences, Kampala, Uganda.
BMC Infect Dis. 2018 Feb 21;18(1):87. doi: 10.1186/s12879-018-2992-1.
Smear microscopy lacks sensitivity especially in HIV co-infection, resulting in undiagnosed tuberculosis (TB) and high mortality. The loop-mediated isothermal amplification (TB-LAMP) assay can be staged with minimal infrastructure, is rapid, low cost and detection can be with the naked eye. We assessed feasibility and performance of Eiken TB-LAMP test at point-of-need in TB diagnosis in a high prevalence TB/HIV rural setting in Uganda.
From October 2013-February 2014, TB-LAMP testing was performed on sputum specimens from outpatient presumptive TB adults at a district hospital and two low-level health centers in Kiboga District where smear microscopy is the available routine diagnostic option. TB-LAMP was performed by a technician after a week of training in the district hospital. The technician had no prior experience in the technology. Samples from the low-level health centers were transported to the district hospital for TB-LAMP.
Of the 233 presumptive TB (126 at hospital); 113 (48.5%) were HIV-infected; 129 (55%) male; median age 40 (IQR 30-53). Compared to MTB culture, overall sensitivity and specificity of TB-LAMP were 55.4% (95 CI 44.1-66.3) and 98.0% (95 CI 94.3-99.6) respectively. Among HIV-infected participants, TB-LAMP sensitivity and specificity were 52.3% (95 CI 36.7-67.5%) and 97.1% (95 CI 89.9-99.6) respectively; and 24.4% (95% CI 12.9-39.5) and 98.6% (95% CI 95.1-99.8) respectively among smear-negatives. TB-LAMP sensitivity and specificity were 62.2% (95% CI 44.8-77.5) and 97.8% (95% CI 92.1-99.7) in the hospital setting where central testing occurred compared to 50.0% (95% CI 34.9-65.1) and 98.4% (95% CI 91.2-100) respectively in low-level health centers where specimens were transported centrally.
In this high prevalence TB/HIV rural setting, TB-LAMP performs better than conventional smear microscopy in diagnosis of MTB among presumptive TB patients although the sensitivity is lower than that reported by the World Health Organization. TB-LAMP can easily be performed following a short training period and in absence of sophisticated infrastructure and expertise.
涂片显微镜检查的敏感性尤其在 HIV 合并感染时较低，导致结核病（TB）漏诊和高死亡率。环介导等温扩增（TB-LAMP）检测可以在最低基础设施下进行，快速、低成本，并且可以用肉眼检测。我们评估了在乌干达一个高 TB/HIV 农村地区，在需要时使用 Eiken TB-LAMP 检测在 TB 诊断中的可行性和性能。
从 2013 年 10 月至 2014 年 2 月，在基博罗县的一家区医院和两家低级别卫生中心对门诊疑似 TB 的成年患者的痰标本进行 TB-LAMP 检测，这些中心的常规诊断方法是涂片显微镜检查。TB-LAMP 由一名在区医院接受一周培训的技术员进行。该技术员在此项技术上没有任何先前经验。来自低级别卫生中心的样本被运送到区医院进行 TB-LAMP。
在 233 例疑似 TB（医院 126 例）中，113 例（48.5%）为 HIV 感染者；129 例（55%）为男性；中位年龄 40 岁（IQR 30-53）。与 MTB 培养相比，TB-LAMP 的总敏感性和特异性分别为 55.4%（95%CI 44.1-66.3）和 98.0%（95%CI 94.3-99.6）。在 HIV 感染者中，TB-LAMP 的敏感性和特异性分别为 52.3%（95%CI 36.7-67.5%）和 97.1%（95%CI 89.9-99.6%）；而在涂片阴性的患者中，敏感性和特异性分别为 24.4%（95%CI 12.9-39.5%）和 98.6%（95%CI 95.1-99.8%）。在中央检测的医院环境中，TB-LAMP 的敏感性和特异性分别为 62.2%（95%CI 44.8-77.5%）和 97.8%（95%CI 92.1-99.7%），而在中央运送标本的低级别卫生中心，敏感性和特异性分别为 50.0%（95%CI 34.9-65.1%）和 98.4%（95%CI 91.2-100%）。
在这个高 TB/HIV 农村地区，TB-LAMP 在诊断疑似 TB 患者的 MTB 方面比传统的涂片显微镜检查要好，尽管敏感性低于世界卫生组织报告的水平。TB-LAMP 可以在经过短期培训后，在没有复杂基础设施和专业知识的情况下轻松进行。
