Mycobacterial Diseases
Open Access

Using Bronchoalveolar Lavage Fluid for Active Pulmonary Tuberculosis Laboratory Diagnosis

Ying He¹, Song Yang^1*, Tong-Xin Li^1*, Jian-Qiong Guo², You-Ming Fan³, Mei Han¹, Xiao-Feng Yan¹, Wu-Yang Yue¹, Qian Qiu¹, Le-Le Wang¹, Qiang-Zhong Sun¹ and Ling Jiang^{1 *}Correspondence: Song Yang, Chongqing Public Health Medical Center, Chongqing, China, Email: Tong-Xin Li, Chongqing Public Health Medical Center, Chongqing, China, Email:

Author info »

Introduction

Mycobacterium tuberculosis (MTB) culture is recognized as the gold- standard of laboratory method for Tuberculosis (TB) infection diagnosis; however, it is difficult to perform when patient’s sputum availability is poor. Tuberculosis (TB) is an ancient infectious disease caused by Bacillus MTB, which usually infect the lung and cause Pulmonary Tuberculosis (PTB). Globally, molecular diagnosis methods are strongly proposed by World Health Organization (WHO) in recent years. Despite the progresses in diagnostics methods, a considerable proportion of TB cases reported were clinically diagnosed rather than laboratory confirmed. In 2016, for example, only 57% of the reported PTB cases were bacteriologically confirmed [1]. In China, unfortunately, it is estimated to be 30% [2], much lower than world average. Therefore, Chinese government have set up the strategy goal of improving PTB pathologic diagnostic rate to over 50% by 2020 in the “13^th five-year national plan for tuberculosis prevention and control” [3].Corresponding to this, the Chinese National Pulmonary Tuberculosis (PTB) diagnosis standards were revised on May 1^st, 2017. Currently, one of the challenges for the laboratory diagnosis of Pulmonary Tuberculosis (PTB) lies in obtaining quality clinical samples, especially for sputum-scarce patients. However, BronchoAlveolar Lavage (BAL) is a safe and well tolerated sampling technique for bronchoalveolar cell [4], and BronchoAlveolar Lavage Fluid (BALF) obtained during the bronchoscopy is available for Pulmonary Tuberculosis (PTB) laboratory diagnosis [5]. However, published data about Pulmonary Tuberculosis (PTB) diagnosis yield via BALF is limited.

Materials and Methods

A retrospective evaluation within 16 months (from January 2017 to April 2018) was conducted. Bronchoscopy and BronchoAlveolar Lavage (BAL) were performed for 313 patients suspected of Pulmonary Tuberculosis (PTB) who either had negative sputum smears for Acid-Fast Bacilli (AFB) or could not grow on liquid medium. Patients were diagnosed as APTB if they meet WHO criteria’s [6]. Those with Sputum Smear-Negative Pulmonary Tuberculosis (SSN-PTB) and Sputum Culture-Negative Patients (SCN-PTB) were enrolled.

All patients accepted the following examinations: Electrocardiogram, pulmonary function test, chest CT scanning, prothrombin time test, and routine blood test. If no contraindication for bronchoscopy exists, flexible electric bronchoscopy (Pentax/EB-1530T3, Japan) for trans-nasal or trans oral intubation with 2% lignocaine local injections was conducted after six hours fasting, according to the procedure requirements. 20-30 ml of normal saline was instilled for bronchial washing through the working channel, and then was aspirated into different sterile plastic containers.

BronchoAlveolar Lavage Fluid (BALF) samples were immediately brought to the laboratory, and analyzed with Ziehl-Neelsen Staining Acid-Fast Bacilli Smear Microscopy (Z-N-AFB-SM), Xpert MTB/RIF (Xpert, Cepheid, Sunnyvale, CA, USA), Loop-Mediated Isothermal Amplification (LAMP, Eiken Chemical Co., Ltd, Tokyo Japan), and culture via BACTEC™ Mycobacterial Growth Indicator Tube™ 960 (MGIT, Becton Dickinson Diagnostic Systems, Sparks, MD). Operations and quality controls strictly followed the standard procedure [7-9]. Mycobacterium tuberculosis H37Rv provided by the National Tuberculosis Reference Laboratory (NTRL) (Beijing, China CDC) acted as reference strains.

All patients were tracked for 24-48 hours for adverse events after bronchoscopy, and any symptoms such as pneumothorax, hemorrhage, infection or cardiac arrhythmias were recorded. Bronchoscope was thoroughly cleaned with sterilized water by immersing in 2% glueraldehyde for one hour [4,10]. Anesthetists and well trained respiratory physicians performed the operations. Suspected APTB diagnosis would be confirmed if any one of the laboratory testing mentioned above was positive.

Positive rate of each test was calculated respectively. Chi-square tests for statistical analysis were performed using the SPSS Statistical 20.0 software (Armonk, NY, USA) [11]. A p-value inferior to 0.05 was considered that the difference is significant.

Results

Total 313 suspected APTB patients were enrolled. 71.5% (224/313) were sputum-scarce. 28.5% (89/313) were sputum-sufficient and negative in Z-N-AFB-SM and MGIT 960, and their sputum was collected for further tests. Patient age ranged from 13-80 (mean:34), and 51.1% (160/313) were males. All sputum-scarce patients accepted flexible electronic bronchoscopy and the BronchoAlveolar Lavage Fluid (BALF) were collected (Figure 1).

Figure 1: Flow chart of the study.

89 suspected APTB patients who were sputum-sufficient accepted smearing via Z-N staining and liquid culture via MGIT using both samples of sputum and BronchoAlveolar Lavage Fluid (BALF). BALF-testing confirmed 18 suspected patients (20.2%) via Z-NAFB- SM, and 35(53.0%) were confirmed according to liquid culture via MGIT 960 (Table 1). The difference between sputum and BronchoAlveolar Lavage Fluid (BALF) confirmation rate is significant (χ²=20.02,60.69, P<0.01).

Table 1: BALF and sputum for APTB diagnosis via two methods.

All 313 patients were divided into 2 groups, sputum-scarce and sputum-sufficient. BronchoAlveolar Lavage Fluid (BALF) collected from both groups was tested for MTB via different methods. For the sputum-sufficient group, the diagnosis yields were 20.2% (18/89) via Z-N-AFB-SM, 55.1% (49/89) via Xpert, 57.4% (31/54) via LAMP, 53.0% (35/66) via MGIT. For the sputum-scarce group, the diagnosis yields were 17.4% (39/224), 72.5% (119/164), 63.4% (52/82) and 46.9% (105/224) respectively (Table 2). Chi square tests suggest that there were no significant difference between the two groups by using Z-N-AFB-SM, LAMP, and culture (χ²=0.56, 0.49, 0.77, P>0.05), but were significant by using Xpert (χ²=7.92, P<0.05). In our study, the total positive rate using BronchoAlveolar Lavage Fluid (BALF) was18.2% (57/313) by method of Z-N-AFBSM, 66.4% (168/253) by method of Xpert, 61.0% (83/136) by method of LAMP and 48.2% by method of MGIT respectively. The three methods were all significant higher than Z-N-AFB-SM (χ²=119.30, 60.80, 6.57, P  0.01). Xpert had the highest diagnosis yield, the difference between XPERT and MGIT was significant (χ²=25.60, P<0.05). LAMP had the second highest diagnosis yield, the difference between LAMP and MGIT was significant too (χ²=6.57, P<0.05). But the diagnosis yield between Xpert and LAMP were similar (χ²=2.158, P>0.05).

Table 2: Efficiency of BALF for PTB laboratory diagnosis.

Experienced respiratory physicians who have acquired professional training of electronic bronchoscopy as well as BronchoAlveolar Lavage (BAL) operation and anesthetists who were not well trained operated the BronchoAlveolar Lavage Fluid (BALF) collection. After a serial of laboratory tests mentioned above, the results suggest that the positive rate of Mycobacterium tuberculosis (MTB) discovered in BronchoAlveolar Lavage Fluid (BALF) collected by respiratory physicians are significantly higher than that collected by anesthetists (χ²=22.48, P<0.01). However the total positive rate of Mycobacterium tuberculosis (MTB) discovered in BronchoAlveolar Lavage Fluid (BALF) was 66.5% (Table 3).

Table 3: Positive rate of BALF collected by different doctor.

Tuberculosis focal spreading outside its original site and metastasizing occurred in 4 APTB patients after bronchoscopy and BronchoAlveolar Lavage (BAL). Another 2 patients suffered fever within 1-2 days after bronchoscopy, and the pulmonary foci increased suddenly. Further sputum culture results identified that pseudomonas aeruginosa caused this secondary-acquired pneumonia. All were cured after receiving standard anti tuberculosis or anti-infection treatments. Total adverse events incidence was 1.9% (6/313).

Discussion

BronchoAlveolar Lavage Fluid (BALF) has a similar sensitivity and specificity for APTB laboratory diagnosis. So far, culturing of Mycobacterium tuberculosis (MTB) is still deemed as the gold standard for the diagnosis of Tuberculosis (TB) [12]. In 2013, World Health Organization (WHO) made a revision to Tuberculosis (TB) diagnostic criteria that the positive results tested based on molecular methods are equivalent to the positive results tested by traditional bacteriological methods. BronchoAlveolar Lavage (BAL) was initially used to rinse the bronchial tree with saline in 1970. It evolved to a diagnostic tool in India in 1994 [13]. By sampling broncho pulmonary cells and epithelial lining liquid, it can accurately diagnose many infectious diseases and tumor. It is superior to invasive techniques such as needle aspiration biopsy and thoracoscopy, and can be used to diagnose sputum-negative Tuberculosis (TB) at early stage [4]. The positive rate of TB diagnosis by BronchoAlveolar Lavage Fluid (BALF) is 87% [14], and for sputum smear negative PTB it reaches 68.2% [15]. A total of 1214 tuberculosis patients detected by BronchoAlveolar Lavage Fluid (BALF) from 9 studies showed that the sensitivity and specificity of BALF test are 54% (95% CI:48%-59%) and 97% (95% CI:95%- 98%) respectively [16].

Complementary methods for sputum-scarce APTB are GA collection for three consecutive days, which usually requires hospital admissions and BronchoAlveolar Lavage Fluid (BALF) collections, and may not be achievable in every setting [17]. BAL is a valuable method of respiratory tract investigation [18]. In our study, the results disclosed that the BronchoAlveolar Lavage Fluid (BALF) has a significantly higher yield than that of sputum. For those suspected APTB with negative results using sputum both tested by Z-N-AFB-SM and by culture, 20.2% (18/89) and 53.0% (35/66) were confirmed when tested using BronchoAlveolar Lavage Fluid (BALF). However, there was no significant difference between sputum-sufficient and scarce APTB by using BALF, the diagnosis yields of the two groups appeared consistence.

BronchoAlveolar Lavage Fluid (BALF) has different diagnosis yield using different testing methods. In our study, we found AFB stain was positive in 18.2% (N=313) of BALF via Z-N-AFB-SM, and positive liquid culture was 48.2% (N=290) in BALF via MGIT 960. Our positive rate of Z-N-AFB-SM was slightly lower than other study reported, but the positive rate of culture based on liquid medium was significantly higher than other report based on Lowenstein- Jensen [19]. The reason may be due to the skill proficiency of the operators as well as the different culture medium.

The progress in nucleic acid amplification technology has led to a breakthrough in early detection of pulmonary tuberculosis, which is remarkably superior to traditional sputum smear test. FDA has approved commercial nucleic acid diagnosis kits for tuberculosis laboratory diagnosis, and both BALF and sputum are recommended. BALF can increase the MTB nucleic acid positive rate of SSN-PTB [9]. 25 studies were reviewed, and the sensitivity/ specificity of tuberculosis laboratory diagnosis method by Xpert MTB/RIF and LAMP was 89%/98% and 93%/94% respectively [20]. The sensitivity of BALF for Xpert and smear microscopy was 80%-92.3% and the specificity was 95.8%-98.9% respectively [21- 23]. Among the SSN-PTB, the sensitivity and specificity of BALF tested by Xpert were 60% and 98%. BALF-Xpert could be used as a substitute for transbronchial lung biopsy in sputum-scarce and SSN-PTB [24]. BALF being used via Xpert MTB/RIF for rapid laboratory diagnosis in high TB burden countries can promote TB treatments [22,23]. LAMP is another nucleic acid amplification technology that has been used for rapid diagnosis of TB clinically. WHO recommends LAMP as an alternative method to microscope for the diagnosis of PTB in adults. In our study, the positive yield using BALF was 66.4% (168/253) and 61.0% (83/136) by method of Xpert MTB/RIF and LAMP respectively. Both were significant higher than Z-N-AFB-SM and culture. On the other hand, when comparing the BALF positive yields between the 2 groups patients of sputum-scarce and sufficient, there was no significance, which means BALF for APTB diagnosis are stable and repeatable.

The quality of BALF may be an important contributing factor for its diagnosis yield. BALF collected by well-trained operators had significant higher positivity. Probably attributed to this reason, there were unavoidable adverse events happened. However, it was reported that no significant adverse event was noted for patients or health-care staff recently [25].

Conclusion

It seems sputum-scarce and SSN-PTB or SCN-PTB is a common problem faced by clinicians. BALF has a similar sensitivity and specificity for APTB laboratory diagnosis. It can be used as a complementary diagnostic method for APTB with poor sputum. However, bronchoscopy is an invasive procedure associated with the risk of transmission of Tuberculosis (TB) and other infections. The proficiency of BALF collection is an important factor affecting the detection results.

Acknowledgements

We would like to thank all study participants who were involved and contributed to the data collection. We thank editors and reviewers for their warm works and valuable comments. We especially thank Prof. Shenjie Tang, Beijing Chest Hospital Affliated to Capital Medical University, Beijing, China. For his critical evaluation on the article

Funding

This work was supported by the Joint Medical Research Project of Chongqing Science & Technology Commission and Health Commission in 2020 (No.2020FYYX001).

Availability of Data and Materials

All data generated or analyzed during this study are included in this published article.

Author’s Contributions

SY, QZ-S, LJ, JQ-G, YM-F and XF-Y designed the study. MH, SY, TX-L and WY-Y analyzed the data.MH, JQ-G, QQ and SY drafted the manuscript. SY, QZ-S, LL-W and LJ provided clinical data; TX-L and WY-Y operated the lab testing. SY supervised the study. All authors read and approved the final manuscript.

Ethics Approval and Consent to Participate

The study was approved by the Ethics Board of Chongqing Public Health Medical Center.

References

1. Global tuberculosis report 2017. World Health Organization (WHO). 2017.
2. Hagiwara E, Katano T, Isomoto K, Otoshi R, Yamakawa H, Okuda R, et al. Clinical characteristics and early outcomes of patients newly diagnosed with pulmonary Mycobacterium avium complex disease. Respir Investig. 2019;57(1):54-9.

   [Crossref][Google Scholar][Pubmed]

3. The office of the state council on the issuance of the notice of national tuberculosis prevention and control program in 13th Five-Year. China National TB council. 2017.
4. Radha S, Afroz T, Prasad S, Ravindra N. Diagnostic utility of bronchoalveolar lavage. J Cytol. 2014;31(3):136.

   [Crossref][Google Scholar][Pubmed]

5. Mondoni M, Repossi A, Carlucci P, Centanni S, Sotgiu G. Bronchoscopic techniques in the management of patients with tuberculosis. Int J Infect Dis. 2017;64:27-37.

   [Crossref][Google Scholar][Pubmed]

6. Yan L, Tang S, Yang Y, Shi X, Ge Y, Sun W, et al.  A large cohort study on the clinical value of simultaneous amplification and testing for the diagnosis of pulmonary tuberculosis. Medicine (Baltimore). 2016;95(4).

   [Crossref][Google Scholar][Pubmed]

7. Yan L, Zhang Q, Xiao H. Clinical diagnostic value of simultaneous amplification and testing for the diagnosis of sputum-scarce pulmonary tuberculosis. BMC Infect Dis. 2017;17(1):1-6.

   [Crossref][Google Scholar][Pubmed]

8. Gelaw B, Shiferaw Y, Alemayehu M, Bashaw AA. Comparison of loop-mediated isothermal amplification assay and smear microscopy with culture for the diagnostic accuracy of tuberculosis. BMC Infect Dis. 2017;17(1):1-6.

   [Crossref][Google Scholar]

9. Ramirez P, Valencia M, Torres A. Bronchoalveolar lavage to diagnose respiratory infections. Semin Respir Crit Care Med. 2007;28(5):525-533.

   [Crossref][Google Scholar][Pubmed]

10. Gopathi NR, Mandava V, Namballa UR, Makala S. A comparative study of induced sputum and bronchial washings in diagnosing sputum smear negative pulmonary tuberculosis. J Clin  Diagn Res. 2016;10(3):OC07.

    [Crossref][Google Scholar][Pubmed]

11. Le Palud P, Cattoir V, Malbruny B, Magnier R, Campbell K, Oulkhouir Y, et al. Retrospective observational study of diagnostic accuracy of the Xpert® MTB/RIF assay on fiberoptic bronchoscopy sampling for early diagnosis of smear-negative or sputum-scarce patients with suspected tuberculosis. BMC Pulm Med. 2014;14(1):1-7.

    [Crossref][Google Scholar][Pubmed]

12. Pang C, Wu Y, Wan C, Shen K, Hu Y, Yang T, et al. Accuracy of the bronchoalveolar lavage enzyme-linked immunospot assay for the diagnosis of pulmonary tuberculosis: a meta-analysis. Medicine (Baltimore). 2016;95(12).

    [Crossref][Google Scholar][Pubmed]

13. Hoffman AM. Bronchoalveolar lavage: sampling technique and guidelines for cytologic preparation and interpretation. Vet Clin North Am Equine Pract. 2008;24(2):423-35.

    [Crossref][Google Scholar][Pubmed]

14. Ullmann AJ, Aguado JM, Arikan-Akdagli S, Denning DW, Groll AH, Lagrou K, et al. Diagnosis and management of Aspergillus diseases: Executive summary of the 2017 ESCMID-ECMM-ERS guideline. Clin Microbiol Infect. 2018;24:1-38.

    [Crossref][Google Scholar][Pubmed]

15. Kumar R, Singh M, Gupta N, Goel N. Bronchoscopy in immediate diagnosis of smear negative tuberculosis. Pneumonol Alergol Pol. 2014;82(5):410-4.

    [Crossref][Google Scholar][Pubmed]

16. Tian P, Shen Y, Wang Y, Wan C, Feng M, Zhu J, et al. Diagnostic value of nucleic acid amplification tests on bronchoalveolar lavage fluid for smear-negative pulmonary tuberculosis: A meta-analysis. Biosci Rep.2015;35(4).

    [Crossref][Google Scholar][PubMed]

17. Wang Hw. Bronchoscopic interventional treatment. People's Medical Publishing House, 2017.
18. Domagala-Kulawik J. The relevance of bronchoalveolar lavage fluid analysis for lung cancer patients. Expert Rev Respir Med. 2020;14(3):329-37.

    [Crossref][Google Scholar][Pubmed]

19. Çakır E, Özdemir A, Daşkaya H, Umutoğlu T, Yüksel M. The value of nasopharyngeal aspirate, gastric aspirate and bronchoalveolar lavage fluid in the diagnosis of childhood tuberculosis.  Turk J Pediatr. 2018;60(1):10-13.

    [Crossref][Google Scholar][Pubmed]

20. Yan L, Xiao H, Zhang Q. Systematic review: Comparison of Xpert MTB/RIF, LAMP and SAT methods for the diagnosis of pulmonary tuberculosis. Tuberculosis (Edinb). 2016;96:75-86.

    [Crossref][Google Scholar][Pubmed]

21. Le Palud P, Cattoir V, Malbruny B, Magnier R, Campbell K, Oulkhouir Y, et al. Retrospective observational study of diagnostic accuracy of the Xpert ® MTB/RIF assay on fiberoptic bronchoscopy sampling for early diagnosis of smear-negative or sputum-scarce patients with suspected tuberculosis. BMC Pulm Med. 2014;14(1):1-7.

    [Crossref][Google Scholar][Pubmed]

22. Lu Y, Zhu Y, Shen N, Tian L, Sun Z. Evaluating the diagnostic accuracy of the Xpert MTB/RIF assay on bronchoalveolar lavage fluid: A retrospective study. Int J Infect Dis. 2018;71:14-9.

    [Crossref][Google Scholar][Pubmed]

23. Barnard DA, Irusen EM, Bruwer JW, Plekker D, Whitelaw AC, Deetlefs JD, et al. The utility of Xpert MTB/RIF performed on bronchial washings obtained in patients with suspected pulmonary tuberculosis in a high prevalence setting. BMC Pulm. Med. 2015;15(1):1-5.

    [Crossref][Google Scholar]

24. Mok Y, Tan TY, Tay TR, Wong HS, Tiew PY, Kam JW, et al. Do we need transbronchial lung biopsy if we have bronchoalveolar lavage Xpert ® MTB/RIF?  Int J of Tuberc and Lung Dis. 2016;20(5):619-624.

    [Crossref][Google Scholar][Pubmed]

25. Taton O, Papleux E, Bondue B, Knoop C, van Laethem S, Bauler A, et al. Role of the bronchoalveolar lavage in noncritically Ill patients during the SARS-CoV-2 epidemic.  Pulm Med. 2020.

    [Crossref][Google Scholar][Pubmed]