Peak Flow Measurement Guidelines

Proper Technique for Peak Flow Measurement

The patient should be in a standing or sitting position with the neck in a neutral position, not flexed or extended, and a nose clip is not necessary but may be used, according to the European Respiratory Journal 2
The patient should take a deep breath to reach total lung capacity (maximum inspiration) and place the mouthpiece just past their front teeth and seal their lips tightly around it, as recommended by the European Respiratory Journal 2
The patient should blow out as hard and as fast as possible without hesitation, with the exhalation being forceful and explosive rather than prolonged, as stated in Rhinology 1
Ensure the peak flow meter indicator is at the bottom of the scale (zero position) before starting the test, as advised by the European Respiratory Journal 3

The highest value from three attempts should be recorded, and results are expressed in liters per minute (L/min) on most portable devices, according to the European Respiratory Journal and Thorax 2, 4, 5
For monitoring purposes, measurements should be taken at the same time each day, typically morning and evening, as recommended by Thorax 4
For home monitoring, patients should record their best of three PEF readings twice daily (morning and evening, before treatment), and the average peak flow should be calculated from at least five days of recordings, as advised by Thorax 4, 5
A variability of >10% in adults and >13% in children may be suggestive of asthma, and diurnal variation is calculated as the day's highest PEF minus the day's lowest PEF, divided by the mean PEF for the day, according to Rhinology 1

The peak flow meter should be cleaned regularly according to manufacturer's instructions, as stated in Thorax 5
In clinical settings, disposable mouthpieces should be used for each patient to prevent cross-contamination, as recommended by the European Respiratory Journal 2

Peak flow monitoring can be used to assess response to bronchodilator therapy, as stated in the European Respiratory Journal and Thorax 4, 6
Peak flow is effort-dependent and requires proper technique for accurate results, as noted by the European Respiratory Journal 2
Peak flow variability testing alone is not recommended as the primary objective test to diagnose asthma in children aged 5-16 years, according to the European Respiratory Journal 3