"Comparative study of gastric aspirate and bronchoalveolar lavage smear with CBNAAT examination for diagnosis of pulmonary tuberculosis in sputum smear negative suspected patients".

INTRODUCTION

Pulmonary tuberculosis (TB) continues to pose a significant global health challenge, particularly in low- and middle-income countries (LMICs), where the burden of the disease is highest. Despite advances in medical science, accurate diagnosis of TB remains problematic, especially in patients with negative sputum smear results.

AIMS AND

OBJECTIVES

This study aims to compare the efficacy of gastric aspirate and bronchoalveolar lavage (BAL) smear examinations to that of the Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) for the diagnosis of pulmonary TB in patients who are sputum smear-negative.

METHODS

This prospective observational study was conducted in the Respiratory Medicine department of Sir T Hospital Bhavnagar. The study included sputum smear-negative patients aged 18 years and older who had high clinical and radiological suspicion of pulmonary TB. Gastric aspirate and BAL samples were collected from these patients and analyzed using AFB smear microscopy and CBNAAT. Data were collected over 1.5 years, and the diagnostic yields of the different methods were compared to determine the most effective approach.

RESULTS

The study included 54 participants (24 females and 30 males) aged 20-79 years. The majority of participants exhibited prolonged productive coughs, low-grade fever, weight loss, and loss of appetite. Gastric aspirate AFB smear results were 98.1 % negative and 1.9 % positive, while CBNAAT results showed 88.9 % with no Mtb detected and 11.1 % with Mtb detected without Rifampicin resistance. For BAL, AFB smear results were 94.4 % negative and 5.6 % positive, and CBNAAT results showed 63.0 % with no Mtb detected, 35.2 % with Mtb detected without Rifampicin resistance, and 1.9 % with Mtb detected with Rifampicin resistance.

CONCLUSION

The findings indicate that BAL CBNAAT has a higher diagnostic yield compared to gastric aspirate methods in sputum smear-negative patients. Combining CBNAAT with traditional smear methods enhances the accuracy and timeliness of TB diagnosis, leading to more effective treatment initiation. These results suggest that integrating CBNAAT into routine diagnostic protocols could significantly improve TB management, especially in resource-limited settings. Further research is recommended to optimize these diagnostic approaches for broader application.