Ardizzoni Elisa, Fajardo Emmanuel, Saranchuk Peter, Casenghi Martina, Page Anne-Laure, Varaine Francis, Kosack Cara S, Hepple Pamela
Médecins Sans Frontières, Institute of Tropical Medicine, Antwerp, Belgium.
Médecins Sans Frontières, Paris, France.
PLoS One. 2015 Dec 15;10(12):e0144656. doi: 10.1371/journal.pone.0144656. eCollection 2015.
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
Xpert® MTB/RIF（Xpert）是一种用于同时检测结核病（TB）和利福平耐药性的自动化分子检测方法，被世界卫生组织推荐为疑似患有耐多药结核病（MDR-TB）或艾滋病毒相关结核病患者的首选诊断方法。我们描述了Xpert的性能以及在无国界医生组织支持的18个国家的33个项目中，在常规条件下实施两年期间吸取的关键经验教训，这些项目分布在不同的地理、流行病学和临床环境中。
采用三种策略使用Xpert：第一种是对所有疑似结核病病例作为初始检测，并同时进行显微镜检查；第二种仅用于有耐多药结核病风险、或患有艾滋病毒相关结核病、或疑似儿童结核病的患者；第三种是对这些高危患者作为初始检测，对其他患者作为显微镜检查的补充检测。使用实验室登记册收集常规实验室数据。使用问卷收集后勤方面、人力资源和工具接受度等定性数据。
2011年4月至2012年12月期间，共有52,863份样本接受了Xpert检测。三种不同策略的平均结核分枝杆菌检测率分别为18.5%、22.3%和11.6%。对同时检测的样本结果分析表明，将Xpert作为显微镜检查的补充检测可使实验室结核病确诊率提高49.7%，而用Xpert取代显微镜检查则为42.3%。该检测的主要局限性是不确定结果的发生率较高，这与模块故障、试剂盒版本（G3与G4）和工作人员经验等因素相关。操作和后勤障碍包括基础设施翻新、基础计算机培训、定期仪器故障排除和维护，所有这些都需要大量且持续的支持。
尽管不确定结果发生率较高，但与显微镜检查相比，Xpert的实施是可行的，且显著提高了结核病检测率。Xpert的实施伴随着相当大的操作和后勤挑战。为了进一步实现诊断的去中心化，仍然迫切需要更简单、适合资源匮乏环境的低成本结核病检测技术。
