Why does my child with asthma need a peak flow measurement test?

Peak flow measurement is one of the simplest and most useful tests, both in the office and often at home. The test involves blowing into a handheld device that gives a numerical reading called a peak flow rate, usually expressed in liters per minute. This helps determine how well asthma is controlled. If used daily, it can give an early warning of worsening asthma. As doctors, we love it because we can determine over the phone whether the child is truly having a problem with his or her asthma and subsequently monitor his or her progress without necessarily having to examine the child. Simple as they are, however, they must be obtained through a doctor and instruction must be given in their use.