The role of induced sputum in the diagnosis of pulmonary tuberculosis.
BACKGROUND
Microbiological confirmation of pulmonary tuberculosis (TB) is of paramount importance in the era of immunocompromised host and emergence of multi-drug resistance.


OBJECTIVE
To assess the value of sputum induction (SI) with hypertonic saline nebulization as a diagnostic tool in patients with suspected pulmonary TB who have no/inadequate sputum or have a sputum smear negative for acid fast bacillus (AFB).


METHODS
One hundred patients with clinical and radiological evidence of pulmonary TB with no/inadequate sputum or smear negative with spontaneous sputum were studied. Sputum was induced with 20 mL of 3% hypertonic saline solution delivered through ultrasonic nebulizer. The specimens were subjected to Ziehl Neelsen staining and were examined under oil immersion lens for the presence of AFB. The specimens were also subjected to mycobacterial culture in BACTEC 460 TB system.


RESULTS
Ninety five patients could produce adequate sputum after SI. Sputum from thirty two patients were found to be positive both in smear and culture while sputum from another three patients were smear negative, but culture positive.


CONCLUSIONS
SI is a safe, cheap and non-invasive procedure and provides significant yield in the diagnosis of pulmonary TB; thus, increasing the case detection rate of smear positive pulmonary TB.
Department of Pulmonary Medicine, North Bengal Medical College, Darjeeling, West Bengal, India.
Saurabh
S
Biswas
Anirban
A
Das
Arijit
A
Sinha
Sibes K
SK
Das
Tapan Das
TD
Bairagya
Induced sputum; pulmonary tuberculosis; sputum smear negative