2 hourly PEF for occupational asthma: 5 work days and 3 rest days are minimum requirement using new analysis

The new analysis system in Oasys utilising the area between work and rest curves (ABC) requires less data for a sensitive and specific occupational asthma diagnosis than the Oasys score. For 2-hourly peak expiratory flow measurements, the ABC score requires 5 work days and 3 rest days to give a sensitivity of 68% and specificity of 91%. If less readings per day are analysed, more work days and rest days are needed to achieve the same accuracy. Work days and rest days do not need to be consecutive, so this can be useful in those who have intermittent exposure. The Oasys 2 score requires 3 working weeks with at least 3 consecutive work days in 75% of the weeks and only 4 readings per day to maintain a sensitivity and specificity of 78% and 92% respectively. In conclusion, the ABC score is a useful addition to the Oasys program which will be particularly useful in PEFs that do not fulfil optimal data criteria for the Oasys 2 score.

References

	Moore VC, Jaakkola MS, Burge CBSG, Pantin CF, Robertson AS, Vellore AD, Burge PS, PEF analysis requiring shorter records for occupational asthma diagnosis, Occup Med (London), 2009;59:413-417,

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