RT Journal Article SR Electronic T1 Is FEV1 better than PEF at detecting asthmatic changes in diurnal variation? JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP p4946 VO 38 IS Suppl 55 A1 Kerry-Anne Dennis A1 Vicky Moore A1 Cedd Burge A1 Sherwood Burge YR 2011 UL http://erj.ersjournals.com/content/38/Suppl_55/p4946.abstract AB FEV1 is considered the best measure of airflow obstruction but PEF is more commonly used to diagnose occupational asthma as it's easier to achieve unsupervised. We investigated whether FEV1 or PEF was more sensitive at identifying asthmatic variation when carried out serially at home and at work.Methods: 94 asthmatics from the USA and 84 from the UK were studied. The USA group used the Easyone and the UK group the Piko-1, Vitalograph 2110, or Mini Wright Digital meter. Records contained ≥ 4 readings per day for ≥ 2 weeks with the occupational asthmatic records also having ≥ 10 day shifts. Within session PEF and FEV1 variation was assessed for the USA data (as the meter logged the 3 best attempts) using a coefficient of variation (COV). Diurnal variation% predicted (DV) was analysed for all data. Timepoint analysis (an Oasys program scoring system for occupational asthma) was performed on occupational asthmatics.Results: The table below compares COV and DV for PEF and FEV1 (SD=standard deviation).View this table:There was no significant difference in the number of day shift positive drops (from Timepoint analysis; a drop signifies a significant difference between work and rest) between FEV1 and PEF (p=0.859) and no difference in the value required to produce a positive drop (p=0.297).Conclusion: Diurnal variation is significantly greater for PEF than FEV1 in asthmatics with similar within session variation using logging meters incorporating some quality control. PEF is as good as FEV1 for diagnosing (occupational) asthma.