Shenzhen Key Laboratory of Infection & Immunity, Shenzhen Third People's Hospital (The Second Affiliated Hospital of Shenzhen University), Shenzhen University School of Medicine, Shenzhen, China.
Department of Infectious Diseases, the Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.
Infect Dis Poverty. 2018 Mar 24;7(1):22. doi: 10.1186/s40249-018-0403-x.
The diagnosis of active pulmonary tuberculosis (TB) remains a challenge in clinic, especially for sputum negative pulmonary TB. Bronchoalveolar lavage fluid (BALF) has higher sensitivity than sputum for detection of Mycobacterium tuberculosis (Mtb). However, bronchoscopy is invasive and costly, and not suitable for all patients. In order to make TB patients get more benefit from BALF for diagnosis, we explore which indicator might be used to optimize the choice of bronchoscopy.
A total of 1539 sputum-smear-negative pulmonary TB suspects who underwent bronchoscopy were recruited for evaluation. The sensitivity, specificity and accuracy of Mtb detection in sputum and BALF were compared. Odds ratios and 95% confidence intervals were used to assess variables that associated with positive acid-fast bacilli (AFB) smear, Mtb culture and nucleic acid amplification test (NAAT) of BALF in sputum-negative and non-sputum-producing pulmonary TB suspects.
BALF has significantly higher sensitivity (63.4%) than sputum (43.5%) for Mtb detection by culture and NAAT. 19.7% (122/620) sputum-negative and 40.0% (163/408) non-sputum-producing suspects had positive bacteriological results in BALF. Among sputum-negative and non-sputum-producing pulmonary TB suspects, the positivity of Mtb detection in BALF is associated with a younger age, the presence of pulmonary cavities and a positive result of interferon-gamma release assay (IGRA). Sputum-negative patients under 35 years old with positive IGRA and pulmonary cavity had 84.8% positivity of Mtb in BALF.
Our study indicated that combination of age, the presence of pulmonary cavity, and the result of IGRA is useful to predict the positivity of Mtb detection in BALF among sputum-negative and non-sputum producing pulmonary TB suspects. Those who are under 35 years old, positive for the presence of pulmonary cavity and IGRA, should undergo bronchoscopy to collect BAFL for Mtb tests, as they have the highest possibility to get bacteriologically confirmation of TB.
活动性肺结核（TB）的诊断仍然是临床面临的挑战，尤其是对于痰阴性肺结核。支气管肺泡灌洗液（BALF）比痰液更能提高分枝杆菌（Mtb）检测的敏感性。然而，支气管镜检查具有侵袭性且费用昂贵，并不适合所有患者。为了使 TB 患者从 BALF 检查中获得更多收益，我们探索了哪些指标可用于优化支气管镜检查的选择。
共纳入 1539 例接受支气管镜检查的痰涂片阴性肺结核疑似患者进行评估。比较了痰和 BALF 中 Mtb 检测的敏感性、特异性和准确性。比值比（OR）和 95%置信区间（CI）用于评估与痰涂片阴性和非咳痰肺结核疑似患者 BALF 中抗酸杆菌（AFB）涂片、Mtb 培养和核酸扩增试验（NAAT）阳性相关的变量。
BALF 对 Mtb 培养和 NAAT 的检测敏感性（63.4%）明显高于痰（43.5%）。19.7%（122/620）的痰涂片阴性和 40.0%（163/408）的非咳痰患者 BALF 中细菌学阳性。在痰涂片阴性和非咳痰肺结核疑似患者中，BALF 中 Mtb 检测阳性与年龄较小、存在肺空洞和干扰素 -γ释放试验（IGRA）阳性有关。35 岁以下痰涂片阴性且 IGRA 和肺空洞阳性的患者，其 BALF 中 Mtb 阳性率为 84.8%。
本研究表明，年龄、肺空洞存在和 IGRA 结果的联合可用于预测痰涂片阴性和非咳痰肺结核疑似患者 BALF 中 Mtb 检测的阳性率。年龄在 35 岁以下、肺空洞阳性和 IGRA 阳性的患者，应进行支气管镜检查采集 BALF 进行 Mtb 检测，因为他们最有可能从细菌学上确认 TB。
