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Different Normal Peak Flow Value Scales?


New to forum, but not to having child with asthma.

Can I have thoughts, please.

Our child uses the Mini Wright Low Range PF meter (EN Standard 13826). At almost 4ft 5 inches tall, the Clement Clarke Normal PFV scale would suggest a predicted PEFR of 233. Our GP practice use the EMIS computer system and according to Practice Nurse, when she input our child's details, their average Peak Flow should be 260/270. Now, this is quite a bit different and obviously has implications when we are self monitoring at home with Peak Flow meter (eg they say need to speak with Nurse if PF falls below 240, yet Clement Clarke chart would suggest even 233 is an acceptable PF). Any suggestions as to why there should be such a difference?

Thanks in advance.

5 Replies

use this as a more accurate prediction.

Do not assume that it's 100% accurate, upto 80ltrs/min lower would still be within a normal range.


Thanks for your input. That link would be fine if it was for an adult, but we are talking about a child of under 15yrs.


Hi my Son who is 10 has always had really high peak flows 380 when well, he does lots of sports, so the charts they use are useless for us.We mark his peak flows down and use his highest as when things are well and we have a plan on what to do as the peak flow drops. If it gets to 200 we have to get him into hospital. This may seem high but he deteriorates rapidly and needs specialist help.

My peak flow is 350 my highest so we are all different. I take our peak flow meter with us to appointments. Don't let them tell you things are fine if you feel they are getting out of control, you are the best judge.After eventually getting an appointment, I have spent precious minutes arguing with GPs over peak flows when my Son was seriously ill.Ended up taking him to hospital myself where I was shouted at and told him I should have seen a doctor sooner!!Just trying to follow the rules.Now older and wiser I cut out the middle man.

Good luck



Sorry, didn't realise it never went right down to 0 for age. I'd go with the value from the GP, it has a higher predicted, so you'd basically be getting help sooner when things start to go wrong.

I'll agree with the previous post that it's only a prediction, my predicted is 646, yet I have a personal best of 750. Don't go by peakflows alone though, symptoms and how you feel should also guide you.


Please remember there can be a natural variation with each peak flow meter.

Perhaps take yours / your child's with you to see the asthma nurse etc

Also, check which type of meter scale is being used.

A few years ago, all meter scales were Black (UK version). All new peak flow meters should have a new scale on - the EU scale in line with .... the EU! this is usually yellow.

This will show a difference. As will any chart or software that has any variant.



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