What is spirometry and why does it matter for COPD diagnosis?

Spirometry is a lung function test that measures how much air you can breathe out and how fast. The key result is the FEV1/FVC ratio — forced expiratory volume in one second divided by total forced vital capacity. An obstructive pattern on spirometry is required to confirm a COPD diagnosis. Without it, a diagnosis of COPD based on symptoms and X-ray alone may be incorrect, which means the treatment may not be appropriate either.

If I have been diagnosed with COPD, should I ask about spirometry?

It is a reasonable question to raise with your GP: has a spirometry test been done, and if so, what was the result? The test is non-invasive and involves breathing into a tube at rest and after a bronchodilator inhaler. If spirometry has not been performed, your GP can arrange it — either in the practice if equipment is available, or via a referral to a respiratory laboratory. Do not stop or change any current medication independently; raise the question in a consultation.

Spirometry down 31%: Australia's COPD diagnostic blind spot

What just happened

The Australian Commission on Safety and Quality in Health Care released its Atlas Focus Report on COPD, finding that the national rate of spirometry testing fell by 31 per cent between 2015–16 and 2022–23. Specifically, spirometry performed in GP practices — office-based spirometry — fell by 68 per cent over that same period. Laboratory-based spirometry decreased by only 7 per cent.

A 2024 MedicineInsight report, cited in the Commission’s findings, showed that only 40 per cent of Australians with a documented COPD diagnosis have ever had a spirometry test. That means six in ten people labelled as having COPD — and in many cases, receiving COPD medications — have that label without a confirmatory breath test underpinning it.

As newsGP reported, this matters because COPD cannot be accurately diagnosed from symptoms or a chest X-ray alone. Wheeze, breathlessness, and reduced exercise tolerance have a long differential. Without spirometry demonstrating an obstructive pattern, you are treating a clinical impression, not a confirmed diagnosis.

The both-and

The scale of what’s being missed:

COPD is not a marginal condition. It affects approximately one in 13 Australians over the age of 40 — and about half of those people may not yet know they have it. It was the fifth leading cause of death in Australia in 2023. The communities with the highest COPD prevalence — rural and remote Australia, communities with higher rates of occupational dust exposure, tobacco history, and socioeconomic disadvantage — have the lowest spirometry testing rates. The inverse care pattern is operating in full.

The 68 per cent decline in office-based spirometry is the specific number that should land. The test is not becoming technically harder. The equipment exists. What is declining is the practice’s financial ability and willingness to offer it. NPS MedicineWise has identified the Medicare rebate as a central driver: the existing rebate does not adequately cover the time, training, calibration, and overhead required to deliver spirometry properly. When the rebate doesn’t cover the cost, practices stop offering the test. When practices stop offering the test, patients who need a diagnosis can’t get one where they see their GP.

The treatment paradox:

There is a second finding from the Atlas data worth sitting with: prescriptions dispensed for COPD triple therapy — the most intensive inhaled combination (corticosteroid plus long-acting beta-agonist plus long-acting muscarinic antagonist) — increased by 130 per cent nationally over the same period that spirometry testing was falling. More people receiving complex, escalating therapy. Fewer people with a diagnosis confirmed by the test that COPD diagnosis requires.

That pattern has a name in health systems research: overtreatment on an uncertain foundation. The medications involved are not inherently harmful. But prescribing escalating respiratory therapy without confirming the diagnosis means the question of whether the diagnosis is actually correct never gets asked. It also means that conditions that mimic COPD — asthma, cardiac causes of breathlessness, deconditioning — can remain unidentified while someone is being treated for something else.

The geography of access:

InSight+, the MJA’s clinical news service, has noted that access to spirometry is significantly worse in regional and remote areas, where COPD rates are highest and specialist respiratory services are furthest away. The community most likely to have COPD is least likely to have access to the test that confirms it. That is the asymmetry the Commission’s report is formally documenting.

2 cents

If you have been diagnosed with COPD, or have been prescribed an inhaler for respiratory symptoms, the practical question to raise with your GP: has a spirometry test been done, and if so, what did it show?

The test itself is straightforward — breathing into a tube at rest and after a bronchodilator. The result (an FEV1/FVC ratio below 0.70 post-bronchodilator, per standard diagnostic criteria) either confirms or rules out the obstructive pattern. If you have been managing symptoms for years without that test, asking whether it has been done is a reasonable, low-risk question to raise in a consultation.

If spirometry is not available at your GP practice, it is available at respiratory function laboratories and some specialist clinics. A referral is straightforward. The Lung Foundation Australia has resources for patients navigating lung health in Australia.

This is not a suggestion to change or stop existing medication. An inhaler managing symptoms should not be independently stopped. It is a suggestion to make sure the diagnosis underpinning that management plan has been formally confirmed — because treatment built on an unconfirmed diagnosis may be appropriate, or may be missing something.

This is general information. Spirometry interpretation requires clinical context. What this article is naming is the value of having the test done so that management is built on a confirmed picture.

Verdict

Verdict: yes — worth knowing about.

A 31 per cent national decline in spirometry testing — and a 68 per cent decline in GP practices specifically — means a significant proportion of Australians with a COPD label have never had that label confirmed by the test required to diagnose it. If you or someone you care for has been diagnosed with COPD and is receiving respiratory medication, asking whether spirometry has ever been performed is a reasonable and low-stakes question. The answer changes the clinical picture significantly.