Peak flow chart for monitoring expiratory flow
Due to the wide range of ‘normal' values and high degree of variability, peak expiratory flow is not the recommended test to identify asthma. However, it can be useful in some circumstances.
A small proportion of people with asthma may benefit from regular peak flow monitoring. When monitoring is recommended, it is usually done in addition to reviewing asthma symptoms and frequency of reliever medication use.
Peak flow measurements are most useful if they are displayed on a chart or graph rather than just written down as a list. The Woolcock Institute of Medical Research has developed a standardised and user-friendly peak flow chart so primary carers and patients can monitor symptoms together.