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Faculty of Medicine and Health Sciences > Clinical Skills Centre > Clinical Skills Resources

Peak Flow Procedure


Peak Flow (PF) is a simple and commonly used measurement of lung function. Peak expiratory flow rate (PEFR) is defined as "The maximum flow achievable from a forced expiration starting at full inspiration with an open glottis" (British Thoracic Society and Association of Respiratory Technicians and Physiologists 1994). This is recorded in litres per minute.


Equipment List

Peak Flow Meter
Mini peak flow meter see: for further information

New Meters

Mini-Wright peak flow meters presently in use utilise the Wright McKerrow scale New Mini-Wright peak flow meters are being introduced with the new European Standard (EN 13826) scale these may also be identified by their distinctive yellow dial. This scale differs from the present peak flow meters that are in use. This change has the potential to cause confusion so please ensure you know which peak flow meter you are using and then refer to the correct chart to predict peak flow. The old type peak flow meters will eventually be phased out.