IgE blood levels & spirometry

Had first consultant appointment last week and got bloods done. I have various allergies so wasn't surprised when she decided to get my IgE levels checked. Wanted to know what happens if it comes back high? I realise this confirms an allergy to something but do you then require allergy testing to get to the root of the allergy? Also I realized after the appointment I forgot to tell her I had been taking an antihistamine daily for a month (advised by my gp). Would this affect the IgE reading??

Secondly can spirometry lead to a definitive diagnosis of asthma or other things? Ive had asthma all my life but my recent flare up has both been unusual and not typical of what asthma is like for me. Just wondering what the spirometry outcome might show?

Thanks for reading x

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Hiya, I'll try and help!! Hope cons apt went well!!!

IgE shouldn't be effected be antihistamines, allergic symptoms are caused by the release of histamines, which the antihistamines stop - IgE is different and won't be effected!! They test for specific allergens as well as the total IgE. You can be allergic and still have a low IgE like me.

Spiro on it's own isn't much use, a bit like pf really. If you did pf for the first time it could be a number and you wouldn't know if it was good or bad, it's the same with spiro. Only doing it at clinic every time will you know what's good and what's bad. My FEV1 varies between 3.6 when ok and 1.6 when poorly, but for others my worst can be others best and vice versa, like pf it's very individual. The first time I had spiro done it came back that it was ""normal"" but have since found that it isn't normal and is actually v low for me!! It doesn't rule in or out asthma in isolation it's patterns it follows and variability, just like pf

Hope this is helpful xxx