Respiratory physiology · London
Lung function test, spirometry with reversibility — the first-line respiratory test.
A lung function test is a series of breathing manoeuvres that measure how much and how fast air moves in and out of your lungs — first-line for suspected asthma, COPD, breathlessness and pre-operative assessment.
Key facts
- 01
Definition
Spirometry with post-bronchodilator reversibility — the standardised first-line respiratory test.
- 02
Core measurements
FEV1, FVC and the FEV1/FVC ratio quantify how much and how fast you can exhale.
- 03
Post-bronchodilator reversibility
Repeat spirometry after salbutamol characterises asthma-type reversible airflow obstruction.
- 04
GLI reference values
Results interpreted against Global Lung Function Initiative reference equations, reported as Z-scores.
- 05
Complements other tests
Sits alongside gas transfer (TLCO) and lung volumes when a fuller respiratory picture is needed.
- 06
Same-day report
Interpretation and a written respiratory report are usually available the same day.
Indicative pricing
What a private lung function test costs in London.
Indicative ranges across our partner respiratory laboratories. Send the details and we quote firm figures across two or three options.
In short
A standard spirometry with reversibility: £180–£300, with the report usually the same day.
| Test type | Indicative range | Typical duration | Report turnaround |
|---|---|---|---|
| Standard spirometry with reversibility | £180–£300 | 30 min | Same-day |
| Spirometry + gas transfer (TLCO) | £280–£450 | 45 min | Same-day |
| Full lung function (spirometry, TLCO, lung volumes) | £380–£600 | 60 min | Same-day |
| Lung function + respiratory consultant review | £500–£900 | 75 min | Same visit |
| Pre-operative respiratory work-up | £450–£800 | Half-day | Same-week |
| Urgent same-week lung function | £300–£550 | Half-day | Same-week |
Prices vary by clinic, whether gas transfer and lung volumes are added, and whether a same-visit consultant respiratory opinion is included. We come back with a firm quote within one working day.
Diagnosis steps
From referral to report — what happens, in order.
One respiratory physiologist coaches the manoeuvres, one consultant interprets — often within the same visit.
Phase 1 · Before your test
Referral and inhaler washout
Phase 2 · On the day
~30 minutes in the respiratory lab
- 01
Before
Respiratory referral
A short referral from your respiratory consultant or GP, with the clinical question the test needs to answer.
- 02
Before
Withhold bronchodilators if requested
Short-acting inhalers held for 4–6 hours and long-acting for 12–24 hours, only if your clinician asks.
- 03
On the day
Baseline demographics and height
Age, sex, height and ethnicity are recorded — GLI reference values depend on all four.
- 04
On the day
Three technically acceptable manoeuvres
You perform a series of forced exhalations to ERS/ATS standards, coached by the physiologist.
- 05
On the day
Salbutamol nebuliser
400 mcg of salbutamol via spacer or nebuliser, then a 15-minute wait for the airways to respond.
- 06
On the day
Post-bronchodilator spirometry
The manoeuvres are repeated to measure reversibility of any airflow obstruction.
- 07
After
Interpretation and report
A respiratory physician interprets the trace against GLI norms and issues a same-day written report.
Typical end-to-end: 1–3 days. Urgent cases: same day.
What it shows
What lung function testing can — and can’t — answer.
Spirometry answers a specific question — is airflow obstructed, restricted or mixed, and does it reverse with a bronchodilator.
-
Obstructive pattern (COPD, asthma)
Reduced FEV1/FVC ratio — the hallmark of airflow obstruction in COPD and asthma.
-
Restrictive pattern (ILD)
Reduced FVC with preserved ratio — points toward interstitial lung disease and other restrictive processes.
-
Mixed pattern
Features of both obstruction and restriction — usually needs lung volumes to disentangle.
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Reversibility (asthma)
Significant post-bronchodilator improvement in FEV1 supports a diagnosis of asthma.
-
Small-airways disease
Reduced mid-expiratory flows can flag early small-airways involvement before FEV1 falls.
-
Post-bronchodilator FEV1 change
The magnitude of change guides diagnosis, severity grading and treatment escalation.
-
GLI-based Z-scores
Results reported as Z-scores against Global Lung Function Initiative reference equations.
-
Red flag: severe airflow obstruction with hypoxia — urgent respiratory admission
Severe obstruction with desaturation is not a private outpatient problem — arrange urgent admission.
Treatment options
What follows the diagnosis.
The treatment pathway the report typically opens up — for asthma, COPD and related respiratory disease.
-
Inhaled bronchodilator
Short- and long-acting beta-agonists and antimuscarinics for symptom relief and maintenance in asthma and COPD.
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Inhaled corticosteroid
The controller cornerstone for asthma, reducing airway inflammation and exacerbation risk.
-
LABA + LAMA combo
Dual long-acting bronchodilation for moderate-to-severe COPD and step-up asthma regimens.
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Biologics for severe asthma
Anti-IgE, anti-IL5 and anti-IL4/13 monoclonal therapies for eosinophilic and allergic severe asthma phenotypes.
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Pulmonary rehab
Structured exercise and education programme that improves breathlessness, exercise tolerance and quality of life.
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Smoking cessation
The single most effective intervention to slow FEV1 decline in COPD — pharmacotherapy plus behavioural support.
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Home NIV assessment
Non-invasive ventilation assessment for chronic hypercapnic respiratory failure in advanced COPD or neuromuscular disease.
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Structured respiratory follow-up
Serial spirometry, symptom review and treatment titration by a consultant respiratory physician.
Our vetted London network
A small panel of clinics, we picked them.
Respiratory physiology labs across central, north, west and south London. Introductions are made privately, once we understand your case.
Selection criteria
How we choose every respiratory lab in our network.
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Accredited respiratory physiology laboratories to ARTP standards
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ERS/ATS-compliant spirometry technique with three acceptable manoeuvres
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Same-day report, with traces available for onward review
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Onward respiratory-consultant pathway if significant disease is found
Red flags
When lung function alone isn’t the answer.
These are the findings and clinical scenarios that require urgent respiratory input, imaging or a specialist pathway beyond spirometry.
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FEV1 < 30% predicted
Severe airflow obstruction — needs respiratory-consultant input and consideration of triple therapy or biologics.
-
Hypercapnic respiratory failure
Rising CO₂ with morning headaches or somnolence — flag for arterial gases and home NIV assessment.
-
Rapid FEV1 decline
A steep year-on-year drop warrants urgent respiratory review and reassessment of the underlying diagnosis.
-
Suspected malignancy on imaging
A concerning nodule or mass on chest imaging is a two-week-wait pathway — not a lung-function question.
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Occupational lung disease
Exposure to asbestos, silica or other inhalants needs a targeted respiratory and occupational-health work-up.
-
Alpha-1 antitrypsin deficiency
Young COPD, basal emphysema or a family history warrants alpha-1 antitrypsin testing.
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Asthma-COPD overlap
Features of both diseases in the same patient — needs a considered pharmacological plan by a respiratory specialist.
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Severe eosinophilic asthma
High blood eosinophils with frequent exacerbations opens the door to anti-IL5 biologics.
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Post-COVID lung disease
Persistent breathlessness after COVID-19 may need lung function, gas transfer and cross-sectional imaging.
Reading your report
A lung function report can look intimidating. It isn’t.
Whatever the finding, the report keeps to the same four parts.
A quiet reminder
The report is written for your doctor, not for you — and that’s normal.
If you would like us to talk you through it before your follow-up, just ask.
- 01 Header
Indication and demographics
Your details, height, ethnicity and the clinical question the test was asked to answer.
- 02 Technique
Manoeuvre quality and reproducibility
Which manoeuvres met ERS/ATS acceptability and reproducibility criteria.
- 03 Findings
FEV1, FVC, ratio and reversibility
Pre- and post-bronchodilator values, GLI Z-scores and the change in FEV1 and FVC.
- 04 Impression
The conclusion: read this first
Normal, obstructive, restrictive or mixed pattern — with the concrete next step.
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 lung function testing.
Quick answers on FEV1 and FVC, inhaler washout, reversibility, GLI reference values and when to add gas transfer or lung volumes.
-
What is a lung function test?
A lung function test is a series of breathing manoeuvres — most commonly spirometry with post-bronchodilator reversibility — that measure how much and how fast air moves in and out of your lungs. It is the first-line respiratory test for suspected asthma, COPD and unexplained breathlessness.
-
What do FEV1, FVC and the FEV1/FVC ratio mean?
FEV1 is the volume of air you can force out in the first second of a maximal exhalation. FVC is the total volume you can exhale. The FEV1/FVC ratio tells the respiratory physician whether the pattern is obstructive (low ratio) or restrictive (preserved ratio with low FVC).
-
Do I need to stop my inhalers before the test?
Only if your clinician specifically asks. Short-acting bronchodilators are typically held for 4–6 hours and long-acting bronchodilators for 12–24 hours before reversibility testing — but never stop treatment on your own initiative.
-
What is post-bronchodilator reversibility?
After baseline spirometry you inhale a bronchodilator (usually 400 mcg salbutamol) and wait 15 minutes. Repeat spirometry then measures how much your airways have opened up — significant improvement supports a diagnosis of asthma.
-
What are GLI reference values?
The Global Lung Function Initiative reference equations translate your raw FEV1 and FVC into age-, sex-, height- and ethnicity-adjusted Z-scores. This is the current international standard for interpreting spirometry.
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When would I need gas transfer or lung volumes as well?
When spirometry alone doesn’t answer the question — for example, suspected interstitial lung disease, a mixed obstructive-restrictive pattern, or pre-operative assessment. Gas transfer (TLCO) and body-plethysmography lung volumes are the next steps.
Sources
Clinical guidance underpinning this page.
- NICE. Asthma: diagnosis, monitoring and chronic asthma management (NG245).
- NICE. Chronic obstructive pulmonary disease in over 16s: diagnosis and management (NG115).
- ERS / ATS. Standardisation of spirometry — 2019 update.
- British Thoracic Society. Guidelines for respiratory measurement.
Published 2026-07-30 · Reviewed 2026-07-30 · Next review 2027-07-30 · Reading time 5 min
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In practice, in London
Why private lung function test moves differently in London
With lung function test, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. The NHS route for lung function test is thorough, but the queue is real. Most patients we speak with have been told to expect anywhere from a handful of weeks to several months, depending on their local trust and how the referral is graded. Going private in London usually collapses that window to a matter of days — often the same week if the diary allows. It isn’t about jumping a queue so much as buying time back while you still have the flexibility to plan around it.
Once you’re in the private system for lung function test, the pace picks up noticeably. Consultant slots run to time, imaging is usually available in the same building or a short walk away, and the report comes back typed and detailed. It’s the coordination that tends to feel different — one person on the other end of the phone, not a switchboard. For lung function test specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.
The value of going through a concierge for lung function test isn’t access — anyone with an insurer or a credit card can get a private appointment in London. The value is knowing which consultant reads this particular presentation best, which unit turns reports around fastest, and which pathway won’t hit a dead end if the findings point somewhere unexpected.
Nearby in the library