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Accuracy of Spirometry (Part 2)

This is a continuation from Part 1
I had a friend that just had a spirometry and was told he was 106% of expected. I had him try my meter thinking that his reading would be well below what the spirometry showed for FEV1 however instead it was significantly higher. As he is the same age as I am as well as the same height and weight his FEV1 should have been 3.77 and if you increase it to 106% of expected it should be 3.96 but was 4.46 according to my meter, so if anything it would appear my meter is reading considerably higher than it should be even though my own personal readings seem to be considerably lower than the readings from the spirometry test. I should also mention that if I blow very hard from the start the PEF is quite high, usually in the 525-600 L/min range, but the FEV1 is in the 1.8 to 2.0 range, whereas if I blow more slowly and constantly right from the start like I did during the spirometry test, the PEF is often in the 300-400 L/min range but the FEV1 is in the 2.25 – 2.45 range, which seems completely backwards. One would think if you blew really hard at the start the FEV1 would be higher unless I am running out of breath before the full second is up, but the results do sort of mimic the spirometry tests done in that my PEF was quite low and FEV1 was reasonable.
I guess perhaps my FEV1 has dropped but that would seem to be a very significant drop in a relatively short period of time.

Thank you
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242587 tn?1355424110
Professionally well-performed Spirometric testing is much more reliable, the results more valid than any hand-held device.  Correlation of results from any two such devices may vary significantly depending on which end of the spectrum the values reside.  Your friend’s FEV1 was around 4 L.  Yours in the 2.00-2.50 range, depending on how you “blow”.  

In essence, each should be its own standard for you and correlated with symptomatic relief and that also relates to the concept of the “Personal Best.”  Peak flow measurements are notoriously variable, depending on technique.  I suggest that you review your technique with your doctor’s assistant, a technician in the pulmonary function lab or better yet, with an experienced respiratory therapist.

Good luck
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Thanks very much
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Avatar universal
I live in a small city so the closet place I could get this kind of advice is about 180 miles and it also takes a fair wait.
Thanks again
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