RESUMO
<p><b>OBJECTIVE</b>Assessing the reproducibility of a portable spirometer, including reproducibility of inter-observer and day-today.</p><p><b>METHODS</b>Lung ventilation function was performed in 22 healthy volunteers by two observers on the same day and repeated by the first observer after 24h.</p><p><b>RESULTS</b>The inter-observer and day-to-day intra-class correlation coefficients are all higher than 0.75. There are no significant difference between each other. Bland-Altman chart shows good limits of agreement between inter-observer and day-to-day, only scattered data are outside of the limits of agreement.</p><p><b>CONCLUSIONS</b>The portable spirometer shows good inter-observer and day-to-day reproducibility, and can be used for testing lung function in clinical.</p>