Help understanding Peak Flow readings

Can someone help me understanding Peak Flow?

When I use my peak flow meter I blow around 390. But when I was with the asthma nurse yesterday her meter read 470. Mine has a yellow strip, hers is black.

I found this website (http://www.peakflow.com/top_nav/normal_values/PEFNorms.html) which said there are two types of meter, the Wright-McKerrow scale, which is given in black, and the EU scale, which is shown in yellow. According to the website someone of my age and height should blow 492 on the black scale and 447 on the yellow scale.

Is it all in my head and my asthma isn't as bad as I think it is (bad for me that is), or is my asthma nurse using the wrong meter and therefore getting it wrong?

According to my peak flow meter I used to be able to blow around 440, and now I average around 390, and I don't feel like my asthma is under control like it used to be, but the asthma nurse doesn't think there's a problem so I don't know what to do.

Thanks

Caroline

6 Replies

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  • i'm pretty sure your nurse is using the wrong PF meter - i've had mine about 20 years and mine is the black strip, i thought all surgeries etc would've moved onto the new EU yellow strip one :-s

    I'm not sure about interpreting the readings but surely if you don't feel you're right the nurse / gp should be trying to help you get back to where you think you should be :-s

  • it may also be that when you do your twice daily blows, you (should) be doing it before your medication/inhalers. The readings from your asthma nurse in the day are usually post medication/inhalers. When I have my lung function tests the readings are always a bit higher because of this.

    Lynda :)

  • it may also be that when you do your twice daily blows, you (should) be doing it before your medication/inhalers. The readings from your asthma nurse in the day are usually post medication/inhalers. When I have my lung function tests the readings are always a bit higher because of this.

    Lynda :)

    this is very trew by am peak flow before meds is 430 ish after about 1 hour gose bck to 500 550 !

    mat :)

  • Everyone should be using the newer EU yellow strip peak flow meters these days, I didn't think you could get the old black ones any more so their PF must be a bit old and probably has lost its calibration too!

    Also, please remember everyone is different and there will be some natural variation between each person.

    Some are higher some are lower.

    My best is 180.... for a normal adult person this would be not very good at all but for me, with Brittle Asthma this is my norm, and anything below 150 is not good for me.

    Perhaps take your PF meter with you next time!

    Kate

  • wow, I wish I got that level of improvement Mat!

    Lynda :)

  • In the grand scheme of things it really doesn't matter what scale you use, or even what your peak flow is compared to the average charts that are available.

    What is important is your current peak flow when compared to your personal best, and that your peak flow is remaining fairly stable. As long as you always compare using the same scale (in an ideal world, you should always use the same meter), it doesn't matter what the numbers are.

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