What is asthma | Is it asthma? | Asthma triggers | Managing triggers and allergens | What is asthma control | Allergen control products | Exercise-induced asthma

 

 

Spirometry (sometimes called Pulmonary Function Testing) is considered the gold standard to confirm the diagnosis of asthma. Your physician can explain this test in more detail. Many primary care health care providers have spirometers in their office, but not all, and the test will require being referred to a specialist.

 

Peak expiratory flow (PEF) meters are best used in the ongoing monitoring of asthma and can be used in the office setting or at home. It is the simplest, quickest and cheapest test of how the lungs are functioning.

 

Using a PEF meter can be easy. You take a deep breath in, then blow out as hard and fast as possible into the meter. You will find a handout on how to use a PEF meter here.

 

There can be instances when a persons’ history strongly suggests asthma but their PEF value is normal (e.g.,100% of the predicted value). This does not necessarily mean that you don’t have have asthma. There are a number of reasons why a person with asthma might have a normal PEF reading.

You could be blowing at your personal best today.

Your personal best could be higher than predicted and what is considered a “normal” is actually low for you.

 

Another way to establish a diagnosis of asthma with a peak flow meter is to give the person a quick acting bronchodilator (sometimes called a reliever – see Asthma Medications), wait 15 minutes, and measure the PEF again. This is a good first test for any person who presents with a history of asthma symptoms.

 

Some health care providers ask a person to take ‘serial peak flow readings. The person is given a PEF meter and asked to record their own readings for a week or two. They should write down the best of three blows in the morning and again in the afternoon or evening. PEF is likely to be lowest in the morning and highest later in the day. The highest reading should be from afternoon or evening, and the lowest reading should be from the morning. A variation of 15% or more between the lowest and the highest readings would support a diagnosis of asthma. A variation of 5% is normal. For each person there is a predicted PEF rate, based on gender, age, and height. Your personal best peak flow is the number that you should use to monitor how well your asthma is being managed.