Efficacy of two sputum collection techniques in patients with air flow obstruction

To compare the efficacy of two sputum collection techniques in patients with chronic obstructive pulmonary disease (COPD) in order to diagnose dysplasia or neoplasia.

This was a crossover study design comparing induced sputum with sputum collected at home. One hundred seven patients with COPD were enrolled. Fifty-six were randomized to collect induced sputum first followed by sputum collection at home. Fifty-one randomly assigned patients collected the sputum in reverse order.

The second sputum collection technique for both random assignments gave the greatest yield of adequate sputum. There was no significant difference in efficacy between the collection of the two sputum collection techniques in the presence of the learning (period) effect.

Sputum collection is equally efficacious by the induced method and the home collection method. A learning effect was responsible for the increased yield of sputum abnormalities in the second collection session. Sputum collection at home may facilitate the amount of dysplasic and neoplastic bronchial epithelial changes in heavy smokers with COPD.