METHODS OF EXAMINING INDUCED SPUTUM - DO DIFFERENCES MATTER

Analysis of induced sputum has been proposed as a direct, relatively n oninvasive method for the evaluation of airway inflammation in disease s such as asthma or chronic obstructive pulmonary disease (COPD). An i mportant question in the validation of this technique concerns the pot ential influence of differences in the methods of examining sputum. Up to the present time, two basic techniques for processing sputum have been described. The first approach consists of selecting all viscid po rtions from the expectorated sample, whereas the second approach proce sses the whole expectorate, containing sputum plus saliva. Both proces sing techniques have been shown to provide valid and reliable data on the composition of the cellular and soluble fraction of induced sputum . From the data currently available, it would therefore appear that th e usefulness of induced sputum as a method for assessing airway inflam mation is not influenced by differences in the methods currently used for examining sputum.