Lung function testing: what to expect
Lung function tests, also called respiratory function tests or breathing tests, help your clinician assess how your lungs are working. They measure how much air your lungs hold, how quickly you can move it and how well oxygen passes into your blood, and are used to diagnose and monitor asthma, COPD, lung scarring, breathlessness and occupational lung disease. At Sleep and Lung Care every test is bulk billed with a valid referral and performed at all five clinics — Epping, Brunswick, Doncaster East, Braybrook and Kilmore — by trained respiratory scientists and reported by a respiratory physician.
Tests we perform
- Spirometry, pre and post bronchodilator — the basic breathing test for asthma and COPD
- Gas transfer (TLCO) — how well oxygen moves from the lungs into the blood
- Lung volumes (plethysmography) — total lung capacity and trapped air
- FeNO — airway inflammation in asthma
- Bronchial provocation (mannitol) — helps diagnose asthma when spirometry is normal
- Respiratory muscle strength (MIP, MEP, SNIP)
- 6-minute walk test and ambulatory oxygen assessment
How to prepare
Wear comfortable clothing, avoid a large meal for two hours and vigorous exercise for one hour before your test, and bring all your inhalers and a list of your medicines. Withhold your inhalers for the times shown in our preparation guide below unless your doctor or our reception team has told you otherwise — and never stop a medicine you need to stay safe. Allow 45–90 minutes depending on the tests requested.
How to get tested
Your GP can refer you directly for lung function tests using our referral templates or the online referral form; the report is sent back to your GP. If a specialist opinion is needed, one of our respiratory physicians can see you at the same clinic. Upload your referral to get started.
Preparing for your lung function test
Some medicines hide what the test is trying to measure. Unless your doctor or our reception team has told you otherwise, withhold the medicines below for the times shown before your appointment. Do not stop a medicine you need to stay safe — if you need your reliever, take it and tell the scientist when you arrive; we can still test you or rebook.
| Medicine (examples) | Spirometry, lung volumes, gas transfer, FeNO | Bronchial provocation (mannitol) |
|---|---|---|
| Reliever puffers — salbutamol (Ventolin, Asmol, Airomir), terbutaline (Bricanyl) | 4–6 hours | 8 hours |
| Ipratropium (Atrovent) | 12 hours | 12 hours |
| Twice-daily long-acting and combination inhalers — Seretide, Symbicort, Flutiform, DuoResp, Fostair, Serevent, Oxis | 24 hours | 36 hours |
| Once-daily long-acting inhalers — Breo Ellipta, Trelegy, Anoro, Ultibro, Spiolto, Onbrez, Striverdi | 36–48 hours | 72 hours |
| Twice-daily triple-therapy inhalers (they contain a long-acting anticholinergic) — Trimbow, Breztri | 36–48 hours | 72 hours |
| Long-acting anticholinergics — Spiriva, Seebri, Incruse, Bretaris | 36–48 hours | 72 hours |
| Preventer-only inhaled steroid — Flixotide, Pulmicort, Qvar, Alvesco | Take as usual | Skip the morning dose (6 hours) |
| Montelukast (Singulair) | Take as usual | 4 days |
| Antihistamines — Zyrtec, Claratyne, Telfast, Phenergan | Take as usual | 72 hours |
| Theophylline (Nuelin) | Take as usual | 24 hours |
| Caffeine — coffee, tea, cola, energy drinks, chocolate | Avoid on the morning of the test | 24 hours |
| Smoking or vaping | Not within 1 hour | Not within 1 hour |
| Alcohol | Not within 8 hours | Not within 8 hours |
| Vigorous exercise · a large meal | Not within 1 hour · not within 2 hours | Not within 1 hour · not within 2 hours |
Wear loose clothing, bring all your inhalers and a list of your medicines, and allow 45–90 minutes. Tests are bulk billed with a current referral. If you are unsure about any medicine, call (03) 9422 0077 before your appointment. These instructions were reviewed by our respiratory physicians on 10 September 2026.
Download the lung function test preparation guide (PDF) Upload your referral
After your test
Your tests are performed by a respiratory scientist and reported by one of our respiratory physicians. The report is sent to your referring doctor within two weeks. If your GP referred you for the tests only, your GP goes through the results with you and can ask us for a consultation if the report recommends one; if you are already seeing one of our physicians, the results are discussed at your next appointment. If you have not heard from your doctor three weeks after the test, call (03) 9422 0077.