Explanation

The peak flow test measures how fast and hard you can blow air out of your lungs into something called a peak flow meter. This is usually something that looks like a tube with numbers up the side.

Why do I need one?

Doctors use the peak flow test to see how bad your asthma is, or to see if your asthma is getting worse. They can also tell if your asthma treatment is right for you, and if you need to change your treatment.

What happens before I have it?

You don't really need to do anything to prepare before doing a peak flow test. You should make sure you are not wearing any really tight clothes, so that you can breathe normally, and it's best to stand up while you take the test.

How is it done?

Your doctor or asthma nurse will probably ask you to do a peak flow test when you go to see them about your asthma. You need to take a deep breath in, as big as you possibly can, and then blow into the mouthpiece of the peak flow meter as hard as you can!

You do this three times and the doctor or asthma nurse will make a note of the highest score, using the numbers on the side of the peak flow meter.

The numbers on the meter show how well your airways are working. If the numbers are lower than they should be, it means your airways are narrow and they are stopping you from blowing as fast or as hard as normal.

Your doctor or asthma nurse may give a peak flow meter to take home with you, so that you can monitor your asthma yourself! When you do the test at home, you should do it exactly how your doctor or asthma nurse told you to. You will usually need to do it three times in the morning and three times in the evening, and you need to write down your results each time.

The next time you go to see your doctor or asthma nurse, you can then take these results along and get advice about what to do next.

Does it hurt?

No, the peak flow test does not hurt at all. But if you do it too many times you may feel dizzy!

What happens next?

If your readings are very different every time you take the test, it probably means that your asthma isn't under control properly, and you might need some different medicine.

What if I have any more questions?

If you have any other questions, you can ask your doctor, or chat to other people about peak flow tests in the Medikidz forums and virtual world, Mediland.

How can I track my peak flow on Medikidz?

In our Interactive Area, members can keep a diary of their peak flow every day. You can see what your peak flow looks like over time and print it out to show your doctor!

Members can sign in to use this by clicking Interactive Area in the top menu and selecting Peak Flow Diary. New visitors can register here.