Objective: To compare mycobacterial yield by induced sputum (IS) and gastric lavage (GL), performed on an ambulatory basis in children with probable intrathoracic tuberculosis.
Design: Diagnostic accuracy study.
Setting: Two tertiary care hospitals in Delhi, India.
Patients: Children aged 6 months to 15 years with newly diagnosed intrathoracic tuberculosis.
Methods: GL and IS were performed in children on 2 consecutive days on ambulatory basis. Samples were examined by Ziehl-Neelsen staining and cultured on an automated BACTEC-MGIT 960 system.
Outcome measure: Mycobacterial yields (smear and culture) for the 2 sample types (IS and GL) were compared.
Results: Four hundred three children (56.6% girls), median age 111 months (interquartile range: 68, 144) were enrolled. Overall yield for acid-fast bacilli and/or Mycobacterium tuberculosis (MTB) by either IS and/or GL was 152 (37.7%). Acid-fast bacilli positivity from IS and GL were 5.7% (23) and 10.4% (42), respectively. Confirmed MTB on culture from IS and GL were 17.9% (72) and 32.5% (127), respectively (P < 0.001). IS and GL identified 17 (4.2%) and 73 (18.1%) additional cases respectively when the other method failed to identify MTB. The combined yields (acid-fast bacilli positivity/MTB) with GL and IS on day 1 (115, 28.5%) were less than that obtained from 2 consecutive GL (135, 33.5%), but better than 2 consecutive IS samples (79, 19.6%; P < 0.001).
Conclusion: It is feasible to collect induced sputum and gastric lavage on an ambulatory basis. The yield of MTB obtained by GL is superior to that obtained by IS.