RNA恒温扩增实时荧光检测技术对涂阴肺结核患者支气管肺泡灌洗液检测的价值

Evaluation of simultaneous amplification and testing in bronchoalveolar lavage fluid for diagnosis of patients with smear-negative pulmonary tuberculosis

临床上无痰或涂阴疑似肺结核患者占肺结核患者的绝大多数，因结核分枝杆菌抗酸染色涂片镜检（简称“涂片法”）阳性率低、培养法耗时较长，均不能满足临床对肺结核快速诊断的需求。本研究收集2014年1月至2016年5月在江苏省南通市第六人民医院入院的223例疑似涂阴肺结核患者的支气管肺泡灌洗液（bronchial alveolar lavage fluid，BALF），分别进行涂片法、BACTEC MGIT 960快速液体培养（简称“MGIT960”）及RNA恒温扩增实时荧光（simultaneous amplification and testing for Mycobacterium tuberclosis，SAT-TB）检测。结果显示，MGIT960培养法和SAT-TB检测的阳性率分别为27．04％（43／159）和32．70％（52／159），均明显高于痰涂片的2．52％（4／159），差异均有统计学意义（χ^2值分别为37．97和49．94，P值均〈0．001）。SAT-TB与MGIT960培养法阳性率比较差异无统计学意义（χ^2=1．22，P=0．270）。若以MGIT960培养法阳性为诊断标准，SAT-TB诊断涂阴肺结核的敏感度为86．05％（37／43），特异度为98．15％（53／54）；阳性预测值为97．37％（37／38），阴性预测值89．83％（53／59）。但SAT-TB检测完成时间（1-2h）明显短于MGIT960培养法（2-6周）。因此，对疑似涂阴肺结核患者的BALF采用SAT-TB检测有较大的早期快速诊断价值。

In clinical practice, many patients suspected of having pulmonary tuberculosis （TB） are difficult to be determined as TB due to lack of bacteriological evidence by using the routine laboratory examination methods, such as sputum smear microscopy with low positive rate and sputum culture with a long time getting results. Those methods cannot meet the clinical needs. A total of 223 cases with smear-negative results but suspected of having pul-monary TB, and hospitalized at our hospital from January 2014 to May 2016, were recruited in this study. The bronchoalveolar lavage fluid （BALF） were collected from those patients and the following examinations were performed on all BALF, including smear microscopy, MGIT 960 rapid culture and simultaneous amplification and testing for mycobacterium tuberculosis （SAT-TB）. The results showed that the positive rates of MGIT960 rapid culture and SAT-TB were 27.04% （43/159） and 32. 70% （52/159） respectively, they were all significantly higher than that of smear method （2. 52%, 4/159）, and those differences were statistically significant （χ^2=37. 97 and 49. 94 respectively, P〈0. 001） ; but the positive rate was no statistically difference between SAT-TB and MGIT 960 culture method （χ^2=1.22, P=0. 270）. If MGIT 960 culture was considered as the gold standard method, the sensitivity, specificity, positive predictive value and negative predictive value of SAT-TB was 86.05%（37/43）, 98.15% （53/54）, 97.37% （37/38） and 89.83% （53/59） respectively. However, compared with MGIT 960 rapid culture method, it takes significantly shorter time getting the results by using SAT-TB （1-2 hours vs. 2-6 weeks）. Therefore, there is a great value in early or rapid diagnosis of the pulmonary TB patients with smear-negative results by performing SAT-TB in BALF.