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NICE: GPs should use FeNO and 'twitchiness' tests to confirm asthma diagnosis

GPs will have to carry out a battery of assessments to ensure they have an ‘objective’ diagnosis of asthma – including exhaled FeNO and bronchial challenge tests – under proposed NICE guidance.

The new draft guidelines completely bypass the option to carry out a trial of therapy as means to diagnose asthma – currently advised by the recently updated gold-standard SIGN/BTS guidelines on diagnosis – and will see GPs required to get extra tests to confirm a diagnosis.

These will include in some cases measurement of airways inflammation and hyper-reactivity – or ‘twitchiness’ – for which tests are currently not widely available, even in specialist services.

According to NICE, new guidelines on diagnosis and monitoring of asthma are needed because ‘there is evidence that incorrect diagnosis is a significant problem’.

Studies suggest up to 30% of people do not have clear evidence of asthma and while some may previously have suffered it, many patients will have been wrongly diagnosed as asthmatic, NICE advisers said.

The move was welcomed by GP experts in respiratory medicine although they cautioned that the guidelines would need significant investment to implement – irrespective of whether GPs are expected to perform the tests themselves in primary care, or to refer more patients to secondary care for investigations.

The draft guidelines cover both children and adults, and key recommendations for those aged over five years include the need to carry out ‘objective’ testing to diagnose asthma, including initial spirometry tests, follow-up bronchodilator reversibility (BDR) tests and exhaled FeNO tests.

Bronchial challenge tests are also recommended in some cases where there is still uncertainty over the diagnosis.

Any patients considered likely to have occupational asthma should be referred to a specialist straight away, while for children aged under five, GPs should treat symptoms based on their clinical judgement and only perform further tests once the child is considered old enough to take part – usually at around five years of age.

Dr Kevin Gruffydd-Jones, GPSI in respiratory medicine who practices in Box, near Bath, said that more sophisticated tests would be required in ‘a significant number of cases’.

He continued: ‘Tests for exhaled nitric oxide to measure inflammation, and airways hyper-reactivity tests for “twitchy” airways are not widely used at present. The guidelines don’t specify whether these extra investigations should be done by GPs or specialists  – but whoever does it, this has got big implications if we are going to do more objective tests – it’s either going to mean a lot more referrals to specialist providers, or primary care will need investment to provide these tests.’


NICE draft asthma diagnosis guidelines – key recommendations


Diagnosing asthma: objective tests in adults and children over five

Use spirometry as the first-line investigation in adults and children over the age of five

- FEV1/FVC less than 70% indicates obstructive spirometry

Next offer a bronchodilator reversibility (BDR) test to anyone with obstructive spirometry. Positive BDR result indicated by:

- Improvement in FEV1 of 12% or more, in children aged 5-16

- Improvement in FEV1 of 12% or more plus increase in volume of 200ml or more, in older patients

Offer a FeNO test in adults and young people older than 16 if considering a diagnosis of asthma

- FeNO of 40 ppb or more indicates positive test

Offer a direct bronchial challenge test with histamine or methacholine in adults and young people older than 16 if there is diagnostic uncertainty after a normal spirometry and either:

- FeNO level of 40 ppb or more and no variability in peak flow readings or

- FeNO level of 39 ppb or less with variability in peak flow readings


Diagnosing asthma in under-fives

Treat symptoms based on observation and clinical judgement in children younger than five years. If asthma still suspected, when the child is old enough to take part in objective tests (usually around the age of five), perform these and review the diagnosis

NICE - Asthma: diagnosis and monitoring of asthma in adults, children and young people

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Readers' comments (19)

  • @ 8:51 "...anyone with unexplained breathlessness (alot of which is deconditioning and anxiety) is labelled with asthma and condemned to lifelong inhalers"

    That's one way of looking at it.

    On the other hand, if they're just prescribed salbutamol, you could equally say that these patients with unexplained breathlessness are being prescribed a cheap, safe placebo which, as you concede, makes them feel better.

    I personally see little objection to the use of salbutamol in those who may not have asthma. But when you get onto the more expensive, more side-effect-prone inhalers, the cost/benefit ratio looks different.

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  • No doubt a proper diagnosis is essential. But how much should we do in primary care ? These new machines are expensive and prone to operator error if there are not enough tests done. It is best to do these in Secondary care.
    But we should stop worrying about referring patients when needed. We DO SEE 91 % of all NHS consultations on 8% of the budget. Quite enough, I contend.

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  • We don't need more tests, we need properly trained GPs and Nurses who can make a robust clinical diagnosis. Seeing erroneous idagnoses of asthma makes my blood boil. This is bread and butter medicine - if you cannot do it you are not competent. Isn't it strange how all our increased regulation/monitoring/revalidation does not protect agains falling standards?

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  • Reply to Dylan Summers:

    I really do not think that this is good practice.

    1. diagnose
    2 .prescribe
    That's how I was taught.

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  • Spirometry is noncore GMS work..refer to Respiratory Clinic.
    Problem solved!

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  • Spirometry is noncore GMS work..refer to Respiratory Clinic.
    Problem solved!

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  • the draft guidelines are incorrect. fev1 / fvc <70% is no longer accepted. It is now < LLN which is lower limit of normal, which takes account of the patients age and is more accurate. Perhaps the draft guidance team should ensure their current, basic information is up to date before expecting us to carry out more tests. In particular a histamine challenge, which can have severe side effects and therefore, should it be carried out in general practice?.

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  • I've landed on Mars.

    Perhaps we should go back to calling it reversible obstructive airways?

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  • I'm all for good guidance but this is massively flawed (i just read it) in it's estimates for cost effectiveness.

    NICEs price estimate per test:
    Full blood count (eosinophils) = £82.33
    2 week home PEFR monitoring = £21.08
    FENO test = £10.01

    Sometimes they include "doctor time" in the pricing and sometimes they don't. There is no mention of acquisition or training costs, and this is the data they use to decide what is cost effective...

    Some of these new technologies will be very useful but for me, seeing the quality of data they put into their calculations means that i cannot trust their conclusions.

    And that's putting it nicely

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