From changes in recorded values, patients and doctors may determine lung functionality, the severity of asthma symptoms, and treatment.

Measurement of PEFR requires training to correctly use a meter and the normal expected value depends on the patient's sex, age, and height.

Due to the wide range of 'normal' values and the high degree of variability, peak flow is not the recommended test to identify asthma.

A small portion of people with asthma may benefit from regular peak flow monitoring.

Various reference values have been published in the literature and vary by population, ethnic group, age, sex, height and weight of the patient.

[11] Peak flow readings are often classified into 3 zones of measurement according to the American Lung Association;[12] green, yellow, and red.

Doctors and health practitioners can develop an asthma management plan based on the green-yellow-red zones.