Hi, bit of a long ramble this but it might help people just being diagnosed and wondering about peak flow numbers.
If it helps there are some charts you can find online. I found this one (see second page): rcht.nhs.uk/DocumentsLibrar...
However as I understand it, there is really no such thing as a typical peak flow. Age, height and sex make basic differences, reflected in that table, but so will general fitness, exercise, sports activity, health history etc. etc. You name it. What's a good number for you is not the same for someone else.
I started diagnosis four months ago... and its still being refined. I was given a reliever and peak flow meter to test with. I took my peak flow before the inhaler and then again a little while after the inhaler and kept a diary of the numbers for two weeks. In my case, my starting number was quite near the chart expected number, and after the inhaler I was higher than the expected number. The thing was not really what the number was, but what difference the inhaler makes. In my case about 20%.
Also add to that how you feel. I feel rough at 500 and below, good at 600. My personal best, after inhaler, is about 650. These are numbers others dream of. Others are overjoyed to get 400, but struggle around at 320 usually. Some are lower. But that isnt the point. To be 20% down from my normal number is when I have asthma symptoms, or vice versa. Others might find they have similar or different tolerance.
So this showed I needed the inhaler - I have asthma. If I didnt have asthma, there would be little or no difference after the inhaler and definitely not 20%. Some days I was pretty fine anyway and others not so.
Diagnosis is all a bit trial end error. Annoying and frustrating when these days we tend to have a test for everything and an answer in ten days.
After taking my charts back to the nurse and doctor, I was confirmed as a mild sufferer, but 'see how it goes'. I still had just a reliever for use as a when I needed it. Aparently the magic number is needing the reliever more than three times a week.
A month on and one heavy cold/persistent cough later, I was only scoring 400~450, very low for me. So doctor gave me a regular preventer inhaler and my first course of 'pred'. I'm on day two so see how it goes. The journey, diagnosis and management refinement continues...