Sputum induction in adults is a well recognised method of diagnosing pulmonary tuberculosis (TB). However, in children this technique is not regarded as feasible since young children tend to swallow their sputum and do not expectorate. Gastric lavage has been used to obtain microbiological confirmation in children but this requires an overnight fast, repeated specimens, and admission to hospital.

This 2 year study carried out in Cape Town, South Africa compared the yield of Mycobacterium tuberculosis from repeated induced sputum samples with that from gastric lavage in young children from an area with a high rate of HIV and TB. 250 children with suspected TB were studied, the median age being 13 months. A positive smear or culture was obtained from 62 children (25%). Samples from induced sputum and gastric lavage were positive in 54 (87%) and 40 (65%), respectively. Microbiological yield did not differ between HIV infected and HIV uninfected children. Sputum induction was well tolerated, with minor side effects of increased cough, epistaxis, vomiting, and wheeze.

This study shows that sputum induction is safe and useful for microbiological confirmation of pulmonary TB in infants and young children. The authors conclude that this technique is preferable to gastric lavage.