Patient guide · Respiratory · 6 min read
Bronchial provocation tests, methacholine, mannitol and exercise challenge for airway hyper-responsiveness.
Bronchial provocation tests measure airway hyper-responsiveness to help diagnose asthma when spirometry and FeNO are inconclusive. Modern options: methacholine challenge, mannitol challenge and eucapnic voluntary hyperventilation (EVH) or exercise challenge.
Why patients choose us
- 01
Consultant respiratory oversight
Every challenge is supervised by a consultant respiratory physician, with a trained physiologist at the couch.
- 02
Rescue always in the room
Reversibility spirometry and a rescue bronchodilator are within arm’s reach for every test.
- 03
Independent, and free
We are paid by no clinic, so the recommendation is impartial and costs you nothing.
Key facts
What a bronchial provocation test is, in six lines.
The essentials — what the challenge measures, which agents are used, and the guard-rails around it.
In short
A controlled inhalation challenge that measures airway hyper-responsiveness — a negative test largely rules out current asthma.
- 01
What it is
A controlled inhalation challenge to detect airway hyper-responsiveness — the physiological hallmark of asthma.
- 02
Standard agents
Methacholine (direct challenge) and mannitol (indirect challenge) are the standard pharmacological tests.
- 03
For athletes
Eucapnic voluntary hyperventilation (EVH) is the gold-standard for exercise-induced asthma in elite athletes.
- 04
High negative value
A negative test has a high negative predictive value — it largely rules out current asthma.
- 05
Physiologist-led
Requires a trained respiratory physiologist and calibrated dosimeter or nebuliser.
- 06
Rescue on standby
A rescue bronchodilator is immediately available at every dose step.
The problem
When spirometry and FeNO don’t settle it.
Many patients with asthma have normal spirometry and equivocal FeNO between attacks. A bronchial challenge asks a sharper question: are the airways hyper-responsive to a known trigger, in a controlled setting?
-
Cough and wheeze, normal spirometry?
A bronchial challenge distinguishes true asthma from cough-variant mimics.
-
Athlete with exertional wheeze?
EVH is the recognised gold standard for exercise-induced bronchoconstriction.
-
Occupational asthma work-up?
Baseline hyper-responsiveness informs workplace exposure and treatment decisions.
Preparation and testing
From referral to report — what happens, in order.
A single consultant respiratory physician from referral to PD20/PC20 report — often within days.
Phase 1 · Before your test
Referral and washout
Phase 2 · On the day
~90 minutes in the lab
Phase 3 · After
Report to your consultant
- 01
Before
Consultant respiratory referral
Referral from a consultant respiratory physician, with the clinical question stated on the form.
- 02
Before
Withhold bronchodilators
Short-acting bronchodilators withheld for 8 hours, long-acting for 48 hours — check with the clinic on ICS and LTRA timing.
- 03
Before
No caffeine for 4 hours
Avoid coffee, tea, chocolate and cola for at least 4 hours before the test.
- 04
On the day
Baseline spirometry
A baseline FEV1 is measured — the test is only performed if baseline lung function is above threshold.
- 05
On the day
Incremental inhalation
Incremental doses of methacholine, mannitol or EVH minute-ventilation are delivered by dosimeter or nebuliser.
- 06
On the day
Repeat spirometry after each dose
FEV1 is repeated after each dose step until the endpoint or the maximum dose is reached.
- 07
After
PD20 or PC20 reported
The provoking dose or concentration causing a 20% fall in FEV1 is calculated and reported to your consultant.
Typical end-to-end: 7–14 days. Urgent cases: same week.
What it shows
When a bronchial challenge is the right test.
A bronchial challenge answers a specific question — are the airways hyper-responsive, and by how much. These are the presentations we see most.
-
Methacholine PC20
The concentration of methacholine that causes a 20% fall in FEV1 — the direct-challenge endpoint.
-
Mannitol PD15
The provoking dose of inhaled mannitol causing a 15% fall in FEV1 — the indirect-challenge endpoint.
-
Exercise-induced bronchoconstriction
Confirms EIB via exercise challenge or EVH — the standard for athlete diagnosis.
-
Vocal cord dysfunction (differential)
A negative challenge with typical symptoms points toward VCD or another mimic.
-
Post-viral airway hyper-responsiveness
Transient hyper-responsiveness after a viral illness — often self-limiting over weeks.
-
Occupational asthma sensitisation
Baseline hyper-responsiveness informs occupational asthma work-up and workplace exposure decisions.
-
Reversibility with rescue bronchodilator
A rescue bronchodilator is administered at the endpoint — FEV1 recovery is documented.
-
Red flag: baseline FEV1 < 60% predicted — contraindicated, refer for treatment first
The challenge is not performed at low baseline FEV1 — treat the airflow obstruction first.
Next steps
What happens after your result.
The concrete next step your consultant will consider — for a negative test, for a mild positive, and for severe hyper-responsiveness.
-
Reassurance if negative
A negative challenge with a high negative predictive value largely rules out current asthma.
-
Inhaled corticosteroid trial
A trial of ICS is first-line if the challenge is positive and symptoms are consistent.
-
Long-acting beta-2 agonist
Added to ICS as combination therapy where symptom control is inadequate.
-
Leukotriene receptor antagonist
Considered for exercise-induced asthma or where ICS is not tolerated.
-
Biologic therapy for severe asthma
Anti-IgE, anti-IL5 or anti-TSLP biologics for severe, refractory eosinophilic or allergic asthma.
-
Environmental / occupational review
Trigger identification, workplace exposure review and allergen mitigation.
-
Repeat testing after 6–8 weeks
Re-challenge after a therapeutic trial to confirm normalisation of hyper-responsiveness.
-
Respiratory specialist follow-up
Structured follow-up with your consultant respiratory physician to titrate therapy.
Our vetted London network
A small panel of respiratory labs, we picked them.
Partners across central, north, west and south London. Not listed publicly — introductions are made privately, once we understand your case.
Selection criteria
How we choose every lab in our network.
-
Consultant respiratory physicians supervising every challenge
-
ATS/ERS-standardised methacholine, mannitol and EVH protocols
-
Trained respiratory physiologist and calibrated dosimeter or nebuliser
-
Rescue bronchodilator and resuscitation trolley in the testing room
Safety and red flags
When a bronchial challenge is not the right test.
Bronchial challenge is very safe when performed to ATS/ERS standards — but there are absolute and relative contraindications that shape whether it is the right test today.
-
Baseline FEV1 < 60% predicted
The challenge is not performed at low baseline FEV1 — treat the underlying airflow obstruction first.
-
Recent MI or stroke
Absolute contraindication within 3 months — cardiovascular clearance required.
-
Uncontrolled hypertension
Sustained BP above 200/100 mmHg — control first, retest after.
-
Aortic aneurysm
Known thoracic or abdominal aortic aneurysm — challenge deferred and vascular opinion obtained.
-
Pregnancy (relative)
A relative contraindication — challenge only performed when the diagnostic gain is clear.
-
Beta-blocker use
Beta-blockers blunt the rescue bronchodilator response — review medication with your consultant.
-
Poor inhaler technique
Reliable, reproducible spirometry is essential — technique is coached before the challenge starts.
-
Concurrent respiratory infection
Any active respiratory infection within 2 weeks — reschedule to avoid a falsely positive result.
-
Anaphylaxis history to test agent
Known hypersensitivity to methacholine or mannitol — the alternative agent or EVH is used instead.
Sources
The guidelines this page follows. Reviewed annually.
This guide has been written and reviewed against the following international standards.
Editorial policy
Published 2026-07-30. Next scheduled review 2027-07-30.
Clinically reviewed by Pulse Atlas Editorial Board (). Written for patients — not a substitute for individual medical advice.
- 01 Guideline
British Thoracic Society / SIGN Asthma guideline
The UK consensus on asthma diagnosis and management, including the role of bronchial challenge testing.
- 02 Standard
European Respiratory Society technical standard
The ERS technical standard for methacholine, mannitol and indirect airway challenge testing.
- 03 Standard
American Thoracic Society
ATS/ERS joint standardisation of pulmonary function testing and bronchoprovocation.
- 04 Strategy
Global Initiative for Asthma (GINA)
The GINA global strategy for asthma management and prevention, updated annually.
Recognised by major UK insurers
Cover depends on your policy and clinic; we confirm with your insurer before booking.
Frequently asked
Everything we get asked about bronchial provocation tests.
Quick answers on methacholine vs mannitol, EVH, what to stop before the test, and when a negative result is enough to rule out asthma.
-
What is a bronchial provocation test?
A controlled inhalation challenge that measures how reactive your airways are — the physiological hallmark of asthma. You inhale increasing doses of methacholine or mannitol, or perform eucapnic voluntary hyperventilation (EVH), while a respiratory physiologist measures your FEV1 after each step.
-
What is the difference between methacholine and mannitol?
Methacholine is a direct challenge — it acts on airway smooth muscle receptors. Mannitol is an indirect challenge — it triggers airway inflammatory cells to release mediators, which is closer to how asthma is triggered in real life. Mannitol has better specificity for current, active asthma; methacholine has slightly higher sensitivity.
-
Is EVH the same as an exercise challenge?
They are related. Both diagnose exercise-induced bronchoconstriction. Exercise challenge uses treadmill or cycle exertion. EVH uses six minutes of controlled hyperventilation of a dry gas mixture — it is more reproducible, cheaper to run and is the gold standard for elite athlete assessment.
-
What do I need to stop before the test?
Short-acting bronchodilators for 8 hours, long-acting bronchodilators for 48 hours, and caffeine (coffee, tea, chocolate, cola) for 4 hours. Your consultant will advise on inhaled corticosteroids and leukotriene receptor antagonists — usually continued but check first.
-
How safe is a bronchial provocation test?
Very safe when performed to ATS/ERS standards. A rescue bronchodilator is immediately available at every dose step, and the test is stopped as soon as a 20% (methacholine) or 15% (mannitol) fall in FEV1 is reached. You will not leave the department until your FEV1 has returned to baseline.
-
Can a negative test rule out asthma?
A negative bronchial provocation test has a high negative predictive value for current asthma — much higher than spirometry or FeNO alone. It does not rule out asthma that is fully controlled on treatment, and does not rule out a future diagnosis if symptoms change.
Related tests
Looking for a different test?
-
Lung function tests
Spirometry, lung volumes and gas transfer — the baseline of respiratory assessment.
Learn more -
FeNO test
Exhaled nitric oxide — a marker of eosinophilic airway inflammation.
Learn more -
CPET
Cardiopulmonary exercise test — heart and lung performance under load.
Learn more -
All tests
Browse every test and procedure we arrange.
Learn more -
Asthma
Related condition guide.
Learn more -
COPD
Related condition guide.
Learn more -
Continuous Positive Airway Pressure
Related treatment option.
Learn more -
Complementary Alternative Medicine
Related treatment option.
Learn more
In practice, in London
Booking bronchial provocation tests privately in London — what actually happens
With bronchial provocation tests, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. The wait for bronchial provocation tests on the NHS depends heavily on where you live and how urgently the referral is graded. Central and West London private clinics can normally book within a week, with imaging or a procedure slot to follow shortly after. It’s worth being honest about the reason for going private: usually it’s time, not a fundamentally different test.
A private bronchial provocation tests pathway in London usually looks like this: an initial consultation, any diagnostics booked at a nearby facility (most within Zone 1 or 2), and a written report sent to you and your GP within a few days. The consultants we work with hold NHS posts alongside their private lists, which keeps the standards consistent across both settings. For bronchial provocation tests specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.
We’re careful about what a private pathway for bronchial provocation tests can and can’t promise. It can compress a wait, put you in front of a subspecialist quickly, and get a proper report in your hands within a week. It can’t rewrite what the imaging or the bloods say. Setting that expectation up front tends to make the whole experience less stressful.
Nearby in the library