Kim Jee Whang, Patel Hemu, Halliwell Richard, Free Robert C, Glimour-Caunt Alison, Pareek Manish, Woltmann Gerrit, Verma Raman, Perera Nelun, Haldar Pranabashis
Department of Respiratory Sciences, University of Leicester, Leicester, UK
Department of Respiratory Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK.
BMJ Open Respir Res. 2025 Jan 19;12(1):e002624. doi: 10.1136/bmjresp-2024-002624.
Tuberculosis (TB) diagnosis in the UK is impacted by delay and suboptimal culture-based microbiological confirmation rates due to the high prevalence of paucibacillary disease. We examine the real-world clinical utility of Xpert MTB/RIF Ultra (Xpert-Ultra) as a diagnostic test and biomarker of transmissible infection in a UK TB service.
Clinical specimens from suspected TB cases triple tested (smear microscopy, mycobacterial culture and Xpert-Ultra) at University Hospitals of Leicester NHS Trust (1 March 2018-28 February 2019) were retrospectively analysed. Diagnostic sensitivity and specificity were calculated using positive MTB culture and clinical TB diagnosis as reference standards. The QuantiFERON (QFT) positive proportion of pulmonary TB (PTB) contacts was used as a metric of transmitted infection to evaluate Xpert-Ultra and smear grade as markers of infectiousness.
251 samples (188 respiratory) from 231 patients (86 TB) were analysed. Compared with microscopy, Xpert-Ultra had higher diagnostic sensitivity (24.7% vs 78.7%, p<0.001) and comparable specificity (97.5% vs 99.4%). Xpert-Ultra and culture had comparable sensitivity (78.7% vs 71.9%) and specificity (99.4% vs 100.0%). Incorporating Xpert-Ultra with culture increased microbiologically verified diagnosis to 91.7% for PTB and 75.9% for extrapulmonary TB, compared with 85.0% and 44.8%, using culture alone. In PTB, both smear and Xpert-Ultra grade were positively associated with the proportion of contacts testing QFT positive. However, Xpert-Ultra had a higher negative predictive value than smear (QFT-positive contacts 6.7% vs 17.7%).
In low-TB-burden settings, systematic adoption of Xpert-Ultra for clinical assessment of suspected TB can improve the proportion of microbiologically verified diagnoses and improve the stratification of transmission risk.
在英国，由于少菌型疾病的高流行率，结核病（TB）诊断受到延迟以及基于培养的微生物学确诊率不理想的影响。我们在英国的结核病服务中研究了Xpert MTB/RIF Ultra（Xpert-Ultra）作为诊断测试和可传播感染生物标志物的实际临床效用。
回顾性分析了莱斯特大学医院国民保健服务信托基金（2018年3月1日至2019年2月28日）对疑似结核病病例进行三重检测（涂片显微镜检查、分枝杆菌培养和Xpert-Ultra）的临床标本。以结核分枝杆菌培养阳性和临床结核病诊断作为参考标准计算诊断敏感性和特异性。将肺结核（PTB）接触者的全血干扰素γ释放试验（QFT）阳性比例用作传播感染的指标，以评估Xpert-Ultra和涂片分级作为传染性标志物的情况。
分析了来自231名患者（86例结核病患者）的251份样本（188份呼吸道样本）。与显微镜检查相比，Xpert-Ultra具有更高的诊断敏感性（24.7%对78.7%，p<0.001）和相当的特异性（97.5%对99.4%）。Xpert-Ultra和培养具有相当的敏感性（78.7%对71.9%）和特异性（99.4%对100.0%）。与单独使用培养相比，将Xpert-Ultra与培养相结合可使PTB的微生物学确诊诊断率提高到91.7%，肺外结核提高到了75.9%，而单独使用培养时分别为85.0%和44.8%。在PTB中，涂片和Xpert-Ultra分级均与QFT检测阳性的接触者比例呈正相关。然而，Xpert-Ultra的阴性预测值高于涂片（QFT阳性接触者分别为6.7%对17.7%）。
在结核病负担较低的环境中，系统采用Xpert-Ultra对疑似结核病进行临床评估可提高微生物学确诊诊断的比例，并改善传播风险分层。
