The "personal best" peak expiratory flow (PEF) is the highest peak flow number you or your child can achieve over a two to three week period when your condition is under good control. Good control means you feel good and do not have any symptoms from your condition.
Your personal best PEF is important because it is the number to which all of your other peak flow readings will be compared. You may have worked with your healthcare professional to develoop an action plan that is based on this number.
You should always use the same peak flow meter and write your readings in your peak flow chart. Then, continue to take peak flow readings each morning. Daily readings will help you to recognize early drops in airflow and changes with the control of your condition.