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Feelings about FeNo testing

risabel59 profile image
11 Replies

I have read a lot of comments about FeNo testing recently and am very interested to know different viewpoints. My consultant said it was going to become part of the gold standard for testing for asthma and lung inflammation and should be in every surgery. He even thinks eventually we (us with asthma) should be using FeNo meters at home the way we use peak flow meters at present. I have mixed feelings about it. What does everyone else think?

My situation is tricky, as I go from having amazing lung function through to being quite unwell quite quickly, where my Pef drops by 50% and Fev1 by 500mls. But my past FeNo tests have not been done when I was sick, so look very normal!! Ie steroids were working just fine. I definitely have asthma it has been diagnosed over and over again since I was a child and is completely reversible, even though I now have some airway remodeling.

So I am wondering if this could be a disaster in the hands of generalist GP’s and Nurses?

What does everyone think?



11 Replies
Lysistrata profile image

Ha. I expect you've already seen some comments of mine about this, but I am genuinely not happy about this push to get FENO in everywhere and the way it's seen by some medics as a kind of magic tool.

I'm sure it absolutely is useful for some people, but equally it ISN'T useful for everyone, and I already have major problems with NICE (who are very keen to push FENO)'s approach to asthma and their obsession with undiagnosing people who don't fit their views about asthma. (For example their approach to spirometry and obstruction - why on earth are they so rigid about not doing reversibility if you have no obstruction to start, when those results are based on population averages, and obstructive ratios in reality often aren't even properly adjusted for age/sex/gender? Why do they go on about needing objective evidence of asthma, then reject doing reversibility, which could provide some of that objective evidence, if someone isn't textbook to start? That's a different topic but it's part of my frustration given they're so into FENO).

My views on FENO:

1) For SOME people with Type 2 (eosinophilic and/or allergic) inflammation, FENO can be useful **as part of the overall picture**

2) For SOME people with Type 2 inflammation, it isn't as helpful. I know of at least one person on this forum with eosinophilic asthma whose FENO is out of step - it's low when they're first exacerbating and goes up when they recover. If you went by FENO alone you'd say they're fine and not exacerbating when they are. Supposedly (see point 1 and below), it should be used as part of the overall picture, but that often isn't the case in reality.

3) ***Not everyone has asthma with allergic/eosinophilic inflammation!!*** We don't know as much about these types of asthma but it seems that's a licence for some people (like my consultant) to be so uncomfortable about dealing with it that they just prefer to see it as not really a major issue and to fixate on FENO and the asthma there are more treatments for. (This is my opinion admittedly, but I've also heard my consultant say things about non-eosinophilic asthma I know from my work and reading the literature are simply not true. He may be an expert and I am not, but I can read scientific and medical literature, I am paid to do that, and I know other experts don't agree with him.)

4) We don't live in an ideal world, and we especially don't live in one where asthma in the UK is concerned. You can call me cynical and you might be right. but it's based on experience and our stats don't exactly show a very rosy picture, nor have they improved despite the findings 7 years ago from the National Review of Asthma Deaths. Sure, some of those problems might be helped by FENO in some cases (like undetected inflammation), but many won't (like ignoring escalating symptoms, undertreating, and not referring appropriately).

All very well to say FENO won't be used in isolation and people won't be told they don't have asthma if theirs is low when it's measured - but in reality, it already is used this way, too often. Even specialists are doing this - I've heard of them using it above anything else to decide about discharge from hospital despite other factors. (In fact, I find the specialist teams often more prone to seeing things as they should be rather than how they actually are - don't get me started on the documented lack of representation of real world patients in clinical trials, while being told by a specialist I should be more like the trial patients).

Like you, Risabel, I'm pretty variable, but I can't seem to even get my specialist tertiary asthma team to understand that, when it's meant to be a basic feature of asthma. Less academic and specialist doctors can often be better and treat what they see, but it's not a given at all and with what I said above about FENO not even always being in step with other clinical parameters with people it 'should' work for, I don't trust it would be used correctly.

There are plenty of examples of other measures and signs, such as peak flow and spirometry, or wheeze, already being used in isolation to make inappropriate clinical decisions, when they shouldn't be and there's already guidelines about how they should be used. Why do we think FENO will be any different?Are guidelines going to magically become more user-friendly than they already are if FENO is widespread (I think this is a major part of the overall problem with guidelines - the information is there, but it's often SO badly presented it may as well not be)?

Sorry for the massive rant! I'm just really fed up with the way things are at the moment with UK asthma care. I'd be perfectly happy to see FENO being used appropriately, in ways and for people it's helpful for. I just really dislike the way it's being pushed so hard at everyone and the money they want to spend on that, when it seems as if they could spend the money and time looking at how asthma care and medical education on asthma could be improved more broadly. (They may be doing that too, but the overriding message at the moment from many people seems to be focused on how FENO will be the answer.)

I really don't think focusing on FENO to the extent your consultant seems to want/says will happen is the answer to the problems we're having at the moment with asthma care, and if anything pushing it like this could contribute to them.

Ostrowta profile image
Ostrowta in reply to Lysistrata

I am a neutrophil predominant asthmatic. My FeNo looks fine even when in a flare-up. I am also not a big wheeze until after breathing treatments and things loosen up. I am not the typical asthmatic at all. My peak flow were 126% predicted but still showed improvement post bronchodilator...so, I totally understand your frustrations! I do not fit the mold either and would hate to be admitted and discharged by FeNo when it would not give a good picture of my situation.

Wheezycat profile image
Wheezycat in reply to Lysistrata

Just a quifk late comment to say how useful I do find your comments! I always read the ones I spot. I also like Ostrowta's and twinkly29's comments on here. I have no views as yet on Feno, except that I dislike it intensely when things get over simplified. I find it scary.

twinkly29 profile image

Yes, my opinion is that in the hands of many professionals it will be a disaster - for anyone whose asthma gives normal FENO readings where the professionals do not acknowledge that this doesn't rule out asthma or asthma issues. Unfortunately many consultants are so fixed on raised FENO meaning asthma and anything else being disregarded, that it's very difficult for those of us whose asthma doesn't show high FENO to find it remotely useful.

However, for those who DO find it useful (because they have the right type of asthma and so their FENO rises helpfully when there are issues), freer access to to it would of course be beneficial.

One can only hope that it's used with good understanding and awareness of different types of asthma AND as part of a picture in diagnosing and assessing issues. Time will tell!

Edit: and what Lysistrata said above!

Lysistrata profile image
LysistrataAdministrator in reply to twinkly29

Yes, it would be great if it were possible to have cheaper machines so people who find it helpful can access it easily.

It's a bit like peak flow. My relationship with peak flow is complicated (helpful, but as a pattern not a one-off). I know people who find it extremely helpful as a guide to how their asthma is at that moment, not just over time. I absolutely wouldn't want them not to have access to it or for it to be disregarded, but like with FENO, I dislike the way it can be misused ('your peak flow is x so you can't have asthma'). Context is key!

twinkly29 profile image
twinkly29 in reply to Lysistrata

Absolutely agree. Thankfully my current team do use it as a tool and not as "the be all and end all" so when my FENO is low, which it always is, they expect it to be.

Pipsqueak77 profile image

Hi risabel59

I am an asthmatic for whom FeNO works really well - it mirrors my airway inflammation and asthma flares so much better than spirometry or PF which I find pretty useless tbh! It allows me and my team the precision and option to vary the amount of steroid I need ( even on a daily basis if necessary) with just one easy to interpret reading. There are no other asthma tests that are able to do this and I would love a FeNO meter at home so that I could be more in control of my steroid doses in real time day by day.

I am not going to rant on about whether it should or should not be be used for asthma diagnosis ( I will leave that to the professionals!) but I believe that it could be a fantastically useful tool (alongside other tests) for people with diagnosed asthma like mine. After all it fundamentally is detecting airway inflammation which is what asthma is all about.

I realise that it doesn’t work for everyone but there are a lot of asthmatics who could really benefit from regular measurements and thus better steroid monitoring/prescribing.

It shouldn’t be dismissed out of hand… it is another piece of a complicated puzzle and one that should be explored on an individual basis to see if it is beneficial.

Take care


Lynneypin profile image
Lynneypin in reply to Pipsqueak77

Having just had a repeat test which has come back quite high, (well they said it was very high) I’m wondering what your readings are … mine was 105, now 93.

Pipsqueak77 profile image
Pipsqueak77 in reply to Lynneypin

Hi Linneypin

My FeNO levels vary quite a lot! They can be anywhere from 25-30ppb (which is basically pretty normal) to 225ppb which is pretty rubbish!

However as I mentioned above this gives us a good indication of whether I need to raise or lower my inhaled steroids.

I personally just find it really helpful - although I realise it doesn’t suit everyone.

It’s one of those tests a lot people seem to dislike but I’m proof that it can really help sometimes.

Have your team acted upon your high level?

Good Luck 👍😊

Lynneypin profile image
Lynneypin in reply to Pipsqueak77

Thanks. Yes they’ve increased my inhaled steroids

Pipsqueak77 profile image
Pipsqueak77 in reply to Lynneypin

HiThat’s great! Fingers x it will help get your levels/inflammation down before a major flare!!


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