Bronchial challenge (provocation) test
A specialist breathing test that uses a controlled trigger to see whether your airways are unusually 'twitchy', which can help confirm or rule out asthma when other tests are unclear.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A bronchial challenge test checks whether your airways are unusually twitchy by exposing them to a controlled trigger under close supervision.
- It is mainly used when other asthma tests are inconclusive, and is better at ruling asthma out than confirming it.
- Because the test deliberately narrows the airways, it must be done in a properly equipped unit with staff and rescue medicine ready to treat bronchospasm.
- You will usually be given a reliever inhaler afterwards and watched until your breathing returns to normal, and you should arrange transport home.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Can confirm or, more reliably, rule out asthma when other tests have been inconclusive.
Anyone whose baseline lung function is already significantly reduced (for example FEV1 well below the normal range), as further narrowing would be unsafe.
You are given a reliever inhaler and your spirometry is rechecked to confirm your airways are opening up again.
Observation until breathing returns to near baseline, with a reliever given and spirometry rechecked.
You are given a reliever inhaler and your spirometry is rechecked to confirm your airways are opening up again.
You stay under observation until your breathing settles back towards your starting level. Mild shakiness from the...
Avoid strenuous activity. Most people feel back to normal but should take it easy. Arrange for someone to take you...
If symptoms briefly return, use your reliever as advised. The result is interpreted alongside your history and...
What is a bronchial challenge (provocation) test?
A bronchial challenge test deliberately exposes your airways to a controlled trigger to see how easily they narrow. Airways affected by asthma are often unusually sensitive, or 'twitchy' (this is called airway hyperresponsiveness), and narrow more than healthy airways would.
Some challenges use an inhaled medicine that acts directly on the airways, such as methacholine. Others use an indirect trigger, such as inhaled mannitol powder, hypertonic (salty) mist or exercise, which provoke narrowing only if the airways are already inflamed. Spirometry is measured before and after each step to track any change.
It is usually only done when asthma is genuinely suspected but ordinary tests, such as spirometry, reversibility, FeNO and peak flow, have not confirmed or excluded it. A key feature is that the test is better at ruling asthma out than ruling it in: a negative test makes asthma unlikely, while a positive test supports it but is not proof on its own.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
Direct challenge (methacholine or histamine)
An inhaled medicine acts directly on the airway muscle to make it narrow. Often reported as the dose or concentration that causes a 20% fall in FEV1 (the PD20 or PC20).
Mannitol challenge
An inhaled dry powder that draws water into the airways and triggers narrowing only if they are already inflamed — an 'indirect' challenge.
Hypertonic saline challenge
Inhaling a salty mist as an indirect trigger of airway narrowing, sometimes also used to collect a sputum sample.
Exercise challenge
Controlled exercise, often on a treadmill or bike, to look for exercise-induced narrowing of the airways.
Preparing for your test
- Ask in detail which inhalers and medicines to stop and for how long — many asthma inhalers, antihistamines and some other medicines must be paused for set periods or the test will be inaccurate.
- Avoid caffeine (coffee, tea, cola, chocolate) on the day, as it can affect the result.
- Do not smoke or vape on the day, and avoid strenuous exercise beforehand.
- Tell the team about heart problems, high blood pressure, an aneurysm, pregnancy or breastfeeding, recent eye or chest surgery, or a recent stroke or heart attack, as these may make the test unsafe.
- Mention any recent cold, flu or chest infection, as this can change how your airways respond.
- Wear comfortable clothing, especially if an exercise challenge is planned.
- Arrange for someone to take you home and do not plan to do anything strenuous afterwards.
What happens
The test is done in a supervised lung function unit by trained staff, with a clinician able to treat severe airway narrowing close at hand and rescue medicines and oxygen ready. First you do baseline spirometry, blowing out hard into a mouthpiece. You then inhale the trigger in gradually increasing doses (or, for an exercise challenge, you exercise to a target level), with spirometry repeated after each step.
The team watches for a fall in your FEV1 — the air you blow out in the first second. The test usually stops once your FEV1 has dropped by a set amount (commonly 20%) or the highest dose has been reached without a significant fall. You may notice chest tightness, wheeze, cough or breathlessness as your airways respond; this is expected and the team is ready for it.
At the end, you are given a reliever inhaler to open the airways again, and your spirometry is rechecked. You are kept under observation until your breathing has returned to normal, usually close to your starting level, before you go home.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Anyone whose baseline lung function is already significantly reduced (for example FEV1 well below the normal range), as further narrowing would be unsafe.
- People with a recent heart attack or stroke, uncontrolled high blood pressure, an aortic aneurysm or unstable heart disease.
- Those who cannot perform reliable spirometry, so the airway response cannot be measured.
- It is the wrong test when asthma is already clear from other tests, or when urgent treatment, not testing, is needed.
Delay or rearrange if…
- You have a recent chest infection, cold or flu, which alters airway reactivity.
- You have not stopped the inhalers, antihistamines or other medicines that must be paused, or have had caffeine on the day.
- You are pregnant or breastfeeding, where some agents are avoided — discuss with the team.
- You have had recent eye, chest or abdominal surgery, or your asthma is currently unstable.
Alternatives to discuss
- Repeat or extended spirometry and bronchodilator reversibility testing.
- FeNO testing to look at airway inflammation.
- Peak flow monitoring at home, including at and away from work for occupational cases.
- Blood eosinophil count as a supporting marker.
- A monitored trial of inhaled treatment with review where appropriate.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Can confirm or, more reliably, rule out asthma when other tests have been inconclusive.
- A negative test makes asthma unlikely, which can spare unnecessary long-term inhaler treatment.
- Can help diagnose exercise-induced or occupational asthma in selected people.
- Gives an objective measure of how sensitive the airways are.
- Done under close supervision, so any airway narrowing it provokes is quickly treated.
Risks & complications
- Chest tightness, wheeze, cough or breathlessness as the airways narrow during the test — expected and treated with a reliever inhaler.
- Light-headedness or coughing from the repeated forceful breathing.
- Mild shakiness or a faster heartbeat from the reliever inhaler given afterwards.
- A stronger drop in lung function than expected, needing more reliever treatment and a longer period of observation.
- Symptoms that take a while to settle, occasionally requiring extra treatment before you can go home.
- An inconclusive result that needs repeating or a different test.
- Headache or flushing with some triggers.
- Severe bronchospasm (a marked, sudden narrowing of the airways) needing prompt emergency treatment — the reason the test is only done in equipped, supervised units.
- With exercise or some agents, effects on the heart such as an abnormal rhythm in susceptible people.
- A late return of symptoms hours after the test in a small number of people.
Because the test deliberately makes the airways narrow, the main risk is bronchospasm — sometimes severe. This is why it is only carried out where a clinician trained to treat acute bronchospasm is immediately available, with reliever medicines, oxygen and resuscitation equipment to hand, and why you are watched until your breathing recovers. It is not done if your baseline lung function is already too low or if you have certain heart conditions, an aneurysm, uncontrolled high blood pressure or a recent heart attack or stroke. Tell the team about all of these and about pregnancy or breastfeeding.
Published figures to discuss
The defining risk of a bronchial challenge is deliberately provoked airway narrowing (bronchospasm), which is usually mild and quickly reversed with a reliever but can occasionally be severe. This is why the test is confined to equipped, supervised units with rescue medicines, oxygen and resuscitation equipment immediately available, and why people with very low baseline lung function or unstable heart disease are excluded. Robust, generalisable numerical rates for severe events are not well established across the different agents and settings, so qualitative wording is used rather than invented figures, and the focus is on supervision and safe selection.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Provoked bronchospasm | Expected possibility; usually mild and reversible | The test deliberately looks for airway narrowing, so it must be supervised with reliever medicine and trained staff immediately available. | Guide sourcesClinical context |
| Severe bronchospasm | Rare in appropriately selected patients | Low baseline lung function, recent attack, current infection or unstable symptoms may make the test unsafe or unsuitable. | Methacholine Challenge Test — StatPearls (NCBI)ncbi.nlm.nih.govSource-linked context |
| False-positive airway hyperresponsiveness | Recognised | A positive test supports asthma but can occur in other airway conditions, after infection or with allergic rhinitis. | Methacholine Challenge Test — StatPearls (NCBI)ncbi.nlm.nih.govSource-linked context |
| False-negative test | Recognised | Recent inhaled steroids, bronchodilators, poor technique or testing away from symptomatic periods can make asthma harder to demonstrate. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
Most people recover within an hour or two as the reliever opens the airways again. You are kept in the unit until your breathing returns to near your starting level. Arrange transport home and take it easy for the rest of the day.
- Some chest tightness, wheeze or cough during and just after the test that eases with the reliever.
- Mild, short-lived shakiness or a faster heartbeat from the reliever inhaler.
- Feeling a little tired after repeated forceful breathing or exercise.
- Breathing returning towards your usual baseline before you leave.
Aftercare
- Stay until the team is satisfied your breathing has returned to near your starting level.
- Use your reliever inhaler as advised if symptoms return later in the day.
- Restart any inhalers or medicines you were asked to pause, as instructed.
- Avoid strenuous activity for the rest of the day and arrange your transport home.
- Ask for your result, including the dose or trigger needed to narrow your airways, and what it means.
- Contact the unit, or seek urgent help, if breathlessness or wheeze does not settle with your reliever.
- Keep a note of the result to compare if testing is repeated.
- A clear list of which inhalers and medicines to pause, and for how long
- Avoided caffeine and not smoked or vaped on the day
- A note of heart problems, high blood pressure, aneurysm, pregnancy or recent surgery
- Comfortable clothing (especially for an exercise challenge)
- Someone to take you home
- Your own reliever inhaler with you
- The unit's contact number in case symptoms return
⚠ Get urgent help if…
- Breathlessness or wheeze after the test that does not settle with your reliever inhaler — seek urgent help.
- Being too breathless to speak in full sentences, eat or sleep — this is an emergency, call 999.
- Lips or fingertips turning blue, or feeling drowsy or confused — call 999.
- Chest pain, palpitations or feeling faint during or after the test — tell the team immediately or call 999.
- A return of severe wheeze or tightness hours after going home that your reliever does not control.
- Needing your reliever far more often than usual in the hours after the test.
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
The result describes how easily your airways narrowed. For a direct challenge such as methacholine, it is often given as the dose or concentration that caused a 20% fall in your FEV1 (the PD20 or PC20): the smaller the dose needed, the more sensitive, or 'twitchy', the airways. For indirect challenges (mannitol, saline or exercise), a defined fall in FEV1 counts as a positive test.
The test is generally better at ruling asthma out than ruling it in. A negative result makes asthma unlikely, while a positive result supports it but can also occur with other conditions, so it is interpreted with your symptoms and other tests. The test cannot grade how severe asthma is day to day, and a positive result is not, on its own, proof of asthma.
Airway sensitivity can change over time with treatment, infections, allergen exposure and other factors, so the result reflects your airways around the time of testing rather than for life. If the clinical picture changes, your clinician may repeat the test or use other assessments, and will advise whether and when retesting is worthwhile.
Related tests, treatments or support
A bronchial challenge test usually comes after spirometry, reversibility testing, FeNO and peak flow monitoring have left the diagnosis unclear. It may be combined with allergy testing or, in occupational cases, with peak flow records kept at and away from work. An exercise or mannitol challenge may be chosen when exercise-induced symptoms are the main concern.
Follow-up & long-term care
Your result is interpreted alongside your history and other tests, either soon after the test or at a follow-up appointment. Depending on the outcome, the next step may be a diagnosis and treatment plan, reassurance that asthma is unlikely, or further tests. You should know who to contact if symptoms return after you leave.
- Repeat challenge testing is occasionally used if the clinical picture changes.
- Continue or adjust inhaled treatment as your clinician advises once any test-day pause is over.
- Bring previous results to reviews so changes in airway sensitivity can be compared.
Repeat, follow-on and what comes next
- An inconclusive or borderline result may need repeating or a different challenge agent.
- A positive result is interpreted with other tests rather than treated as standalone proof of asthma.
- Airway sensitivity can change, so the test may be repeated if the clinical picture changes.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Observation until breathing returns to near baseline, with a reliever given and spirometry rechecked.
- Clear written advice on restarting paused medicines and on what to do if symptoms return.
- A named contact route and escalation plan for breathlessness after discharge.
- Interpretation of the result alongside symptoms and other tests, with a plan for next steps.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The type of challenge used (for example methacholine, mannitol or exercise), as agents and equipment differ.
- The need for a properly equipped, supervised lung function unit with trained staff.
- Who performs and supervises the test and interprets the result.
- The length of monitoring and recovery time required.
- Whether a consultation, explanation of results and any repeat testing are included.
- The specialist centre and its location.
- Which challenge agent will be used and what is included in the price.
- That a properly equipped, supervised unit and trained staff are provided.
- Who will perform and supervise the test and explain the result.
- Whether the reliever inhaler, monitoring and recovery period are included.
- What happens, and what it costs, if the test is inconclusive and must be repeated or changed.
- The cancellation and rescheduling policy, and what happens if you are unwell on the day.
On the NHS? Bronchial challenge testing is available on the NHS in specialist centres, usually when ordinary tests have not confirmed or excluded asthma; private testing is offered in properly equipped lung function units.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not making clear that the test deliberately narrows the airways and can cause wheeze or breathlessness.
- Failing to give precise instructions on which medicines and caffeine to stop beforehand.
- Treating a positive result as definitive proof of asthma without considering other causes.
- No clear plan or contact route if symptoms return after the patient goes home.
Marketing red flags
- Offering the test as a quick, low-risk screen rather than a supervised specialist investigation.
- Performing it outside a properly equipped unit without rescue medicines and trained staff.
- Claiming it can definitively diagnose asthma from a single positive result.
- Down-playing the bronchospasm risk or the need for observation and transport home.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Why is this test being recommended for me, and what will the result change?
- Which trigger will be used, and which inhalers and medicines must I stop beforehand and for how long?
- What happens if my airways react strongly, and how will it be treated?
- What does a positive, negative or borderline result mean for my diagnosis and treatment?
- How long will I need to stay afterwards, and who do I contact if symptoms return at home?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Is a bronchial challenge test available on the NHS?
Is the test safe?
Will it make me wheezy or breathless?
Why do I have to stop my inhalers and avoid coffee?
What does a negative result mean?
Can I drive home afterwards?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: Methacholine Challenge Test — StatPearls (NCBI) NICE NG245 — Asthma: diagnosis, monitoring and management (recommendations) ERS technical standard on bronchial challenge testing — indirect challenges Nonspecific bronchoprovocation testing — review (PMC) Asthma + Lung UK (professionals) — Objective diagnostic testing for asthma
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
Related guides: Reversibility testing · FeNO test (exhaled nitric oxide) · Peak flow monitoring · Body plethysmography (lung volume test) · Bronchial and transbronchial biopsy