RT Journal Article SR Electronic T1 Reference values for peak flow and FEV1 variation in healthy schoolchildren using home spirometry JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1262 OP 1268 DO 10.1183/09031936.00148107 VO 32 IS 5 A1 A. F. J. Brouwer A1 R. J. Roorda A1 E. J. Duiverman A1 P. L. P. Brand YR 2008 UL http://erj.ersjournals.com/content/32/5/1262.abstract AB Current reference values for diurnal peak flow variation in healthy children (median 8.2%; 95th percentile 31%) are so high that considerable overlap exists with those of asthmatic children. These values have been obtained using written peak flow diaries, which are unreliable. The aim of the present study was to obtain reliable reference values for the variation in peak flow and forced expiratory volume in one second (FEV1) in healthy schoolchildren using home spirometry with electronic data storage. Healthy schoolchildren (n = 204; 100 males) aged 6–16 yrs measured their peak flow and FEV1 twice daily for 2 weeks using an electronic home spirometer. The variation in peak flow and FEV1 were calculated as a diurnal amplitude as a percentage of the day’s mean. The mean peak flow variation was 6.2% (95th percentile 12.3%) and the mean FEV1 variation was 5.7% (95th percentile 11.8%). Using home spirometry with electronic data storage, healthy schoolchildren show considerably less peak flow and forced expiratory volume in one second variation than previously reported on the basis of written peak flow diaries. Being the 95th percentiles of the distributions in healthy children, a peak flow variation of 12.3% and an forced expiratory volume in one second variation of 11.8% are suggested as cut-off values for disease when using home spirometry.