Su W J, Tsou A P, Yang M H, Huang C Y, Perng R P
Chest Department, Taipei Veterans General Hospital, Taiwan, ROC.
Zhonghua Yi Xue Za Zhi (Taipei). 2000 Jul;63(7):521-6.
Polymerase chain reaction (PCR) techniques have revolutionized the diagnosis of tuberculosis (TB). PCR has significantly improved the sensitivity and specificity of existing diagnostic methods. In this study, we report our experience using a modified IS6110-based nested PCR assay for rapid diagnosis of pulmonary TB.
A total of 327 respiratory specimens from 275 patients suspected of having pulmonary TB at Taipei Veterans General Hospital were tested using the nested PCR assay, acid-fast smear and culture for the presence of Mycobacterium tuberculosis complex (MTB). Nested PCR was performed with IS6110-based primers specific for MTB. We reviewed the medical records of patients and analyzed the clinical features. The PCR results were compared with the final clinical diagnosis.
We identified MTB in 167 of 327 samples by the nested PCR assay. No non-tuberculous Mycobacterium (NTM) was identified among the clinical samples. Diagnosis by PCR took about 6 hours in this study. The sensitivity and specificity compared with culture were 94.7% and 100%, respectively for the smear-positive, culture-positive samples, and 76.7% and 98.6% for the smear-negative, culture-positive samples. The overall sensitivity, specificity, positive and negative predictive values, compared with culture results, were 91.7%, 98.6%, 98.8% and 90.6%, respectively. Two specimens positive by PCR and negative by culture were taken from patients on anti-TB drug therapy. These specimens were culture-positive before anti-TB drug therapy. After resolution of the discrepancies by studying the patients' clinical data, both specificity and positive predictive value reached 100%.
The results indicated that this in-house nested PCR assay is a rapid and sensitive method for diagnosing pulmonary TB. It is also good for excluding infections caused by NTM.
聚合酶链反应（PCR）技术彻底改变了结核病（TB）的诊断方法。PCR显著提高了现有诊断方法的敏感性和特异性。在本研究中，我们报告了使用改良的基于IS6110的巢式PCR检测法快速诊断肺结核的经验。
对台北荣民总医院275例疑似肺结核患者的327份呼吸道标本进行巢式PCR检测、抗酸涂片和培养，以检测结核分枝杆菌复合群（MTB）的存在。使用针对MTB的基于IS6110的引物进行巢式PCR。我们查阅了患者的病历并分析了临床特征。将PCR结果与最终临床诊断结果进行比较。
通过巢式PCR检测法，在327份样本中的167份中鉴定出MTB。临床样本中未鉴定出非结核分枝杆菌（NTM）。本研究中PCR诊断耗时约6小时。与培养结果相比，涂片阳性、培养阳性样本的敏感性和特异性分别为94.7%和100%，涂片阴性、培养阳性样本的敏感性和特异性分别为76.7%和98.6%。与培养结果相比，总体敏感性、特异性、阳性和阴性预测值分别为91.7%、98.6%、98.8%和90.6%。两份PCR阳性但培养阴性的标本取自正在接受抗结核药物治疗的患者。这些标本在抗结核药物治疗前培养为阳性。通过研究患者的临床数据解决差异后，特异性和阳性预测值均达到100%。
结果表明，这种内部巢式PCR检测法是诊断肺结核的一种快速、敏感的方法。它也有助于排除由NTM引起的感染。
