San Francisco General Hospital, University of California, 94110-0111, USA.
Am J Respir Crit Care Med. 2010 Jan 1;181(1):87-93. doi: 10.1164/rccm.200906-0981OC. Epub 2009 Oct 1.
The contribution of interferon-gamma release assays (IGRAs) to appropriate risk stratification of active tuberculosis suspects has not been studied.
To determine whether the addition of quantitative IGRA results to a prediction model incorporating clinical criteria improves risk stratification of smear-negative-tuberculosis suspects.
Clinical data from tuberculosis suspects evaluated by the San Francisco Department of Public Health Tuberculosis Control Clinic from March 2005 to February 2008 were reviewed. We excluded tuberculosis suspects who were acid fast-bacilli smear-positive, HIV-infected, or under 10 years of age. We developed a clinical prediction model for culture-positive disease and examined the benefit of adding quantitative interferon (IFN)-gamma results measured by QuantiFERON-TB Gold (Cellestis, Carnegie, Australia).
Of 660 patients meeting eligibility criteria, 65 (10%) had culture-proven tuberculosis. The odds of active tuberculosis increased by 7% (95% confidence interval [CI], 3-11%) for each doubling of IFN-gamma level. The addition of quantitative IFN-gamma results to objective clinical data significantly improved model performance (c-statistic 0.71 vs. 0.78; P < 0.001) and correctly reclassified 32% of tuberculosis suspects (95% CI,11-52%; P < 0.001) into higher-risk or lower-risk categories. However, quantitative IFN-gamma results did not significantly improve appropriate risk reclassification beyond that provided by clinician assessment of risk (4%; 95% CI, -7 to +22%; P = 0.14).
Higher quantitative IFN-gamma results were associated with active tuberculosis, and added clinical value to a prediction model incorporating conventional risk factors. Although this benefit may be attenuated within highly experienced centers, the predictive accuracy of quantitative IFN-gamma levels should be evaluated in other settings.
干扰素-γ释放试验（IGRAs）在活动性肺结核可疑者的适当风险分层中的作用尚未得到研究。
确定定量 IGRA 结果是否可改善纳入临床标准的预测模型对痰涂片阴性肺结核可疑者的风险分层。
回顾了 2005 年 3 月至 2008 年 2 月旧金山公共卫生署结核病控制诊所评估的肺结核可疑者的临床数据。我们排除了抗酸杆菌涂片阳性、HIV 感染或年龄小于 10 岁的肺结核可疑者。我们建立了一个用于培养阳性疾病的临床预测模型，并检查了添加定量干扰素（IFN）-γ结果（由 Cellestis，Carnegie，Australia 的 QuantiFERON-TB Gold 测量）的益处。
符合入选标准的 660 例患者中，有 65 例（10%）培养出结核病。IFN-γ水平每增加一倍，活动性结核病的可能性增加 7%（95%置信区间 [CI]，3-11%）。将定量 IFN-γ结果添加到客观临床数据中可显著改善模型性能（c 统计量为 0.71 对 0.78；P < 0.001），并正确地将 32%的肺结核可疑者（95%CI，11-52%；P < 0.001）重新分类为高风险或低风险类别。然而，定量 IFN-γ结果并未显著改善临床医生评估风险提供的风险再分类（4%；95%CI，-7 至 +22%；P = 0.14）。
较高的定量 IFN-γ结果与活动性肺结核相关，并为纳入常规危险因素的预测模型提供了临床价值。尽管这种益处可能在经验丰富的中心会减弱，但应在其他环境中评估定量 IFN-γ水平的预测准确性。
