The Lung Test Reshaping the Gas Exchange Pulmonary Function Testing Market

The Quiet Test That Could Save Millions of Lungs — and Why Investors Are Paying Attention

More than half of patients who recovered from severe COVID-19 showed impaired lung diffusion capacity in follow-up evaluations. That single clinical finding — replicated across hospitals from Milan to Minneapolis — did something unusual: it turned a niche diagnostic procedure into a mainstream medical priority almost overnight.

The test in question is called DLCO, short for Diffusing Capacity of the Lung for Carbon Monoxide. It measures how efficiently gases cross the membrane between your air sacs and your bloodstream. It sounds esoteric. It isn't. It's the kind of test that catches lung disease before a patient feels truly sick, and its growing prominence sits at the center of an expanding medical equipment sector that a detailed pulmonary diagnostics industry overview traces from $260.4 million in 2025 to a projected $442.7 million by 2035.

COPD Is a Bigger Problem Than Most Health Headlines Suggest

Chronic obstructive pulmonary disease killed approximately 3.5 million people globally in 2021 — nearly 5% of all deaths worldwide, according to the World Health Organization. That number tends to get buried beneath cancer statistics and cardiovascular headlines. But COPD's death toll rivals stroke, and unlike many other conditions, it remains dramatically underdiagnosed. In the United States alone, the CDC estimates that roughly 16 million Americans carry a COPD diagnosis while millions more have the disease without knowing it.

This underdiagnosis problem is precisely where gas exchange testing becomes clinically valuable. Spirometry can tell a physician that airflow is obstructed. DLCO testing goes further — it tells them whether the lung tissue itself is compromised at the cellular level. That distinction matters enormously for treatment decisions. A patient with emphysema and a patient with pulmonary fibrosis may present similarly in an office visit, but their gas transfer patterns diverge sharply, and conflating them leads to clinical errors. Pulmonologists have known this for decades. What's changed is the institutional momentum behind making these tests routine rather than specialist-ordered exceptions.

Post-COVID Changed the Calculus

Before 2020, cardiopulmonary exercise testing and diffusion capacity measurement were largely confined to specialty respiratory clinics and academic hospitals. The post-COVID era cracked that boundary open. Long COVID clinics — which proliferated across Europe, the U.K., and North America after 2021 — began incorporating DLCO and related gas exchange assessments as standard components of their evaluation protocols. Institutions like the Cleveland Clinic made these tests central to their post-COVID recovery programs, citing evidence that diffusion abnormalities persisted in patients long after PCR clearance.

The effect on demand was immediate and arguably permanent. Hospital procurement teams that might have considered upgrading their pulmonary diagnostic equipment on a ten-year cycle found themselves acting in two. Companies like Vyaire Medical, which held approximately 31.6% of the relevant market share in 2024, and ndd Medical Technologies — a Swiss firm known for its portable spirometry innovations — saw institutional interest spike. The competitive field also includes Siemens Healthineers, whose April 2025 partnership with Tower Health formalized a ten-year fleet modernization agreement that explicitly covered pulmonology departments.

The Technology Is Evolving Faster Than the Headlines

Open circuit testing systems currently dominate the technical side of this market, holding a 58.4% share as of 2025. The preference isn't arbitrary. Open circuit analyzers are easier for patients to tolerate, produce continuous real-time data, and have benefited from rapid miniaturization. Portable versions now exist that can be used in outpatient settings — even home care environments — which matters considerably given aging demographics in Japan, Germany, and the United States.

The broader trajectory of the gas exchange pulmonary function testing market reflects something worth examining: AI-assisted interpretation is quietly becoming a feature, not a differentiator. Medtronic's HealthCast platform, which won the 2025 MedTech Breakthrough Award for best overall medical device solution, links continuous respiratory monitoring with advanced analytics. Intuitive Surgical's expanding robotic thoracic surgery footprint — roughly 12,000 systems globally as of early 2026 — is generating pre-operative pulmonary assessments at scale, pulling gas exchange testing further into routine surgical prep. These aren't isolated developments. They represent a structural shift in how respiratory data gets collected, interpreted, and acted upon.

Who Gets Left Behind

North America currently commands about 42.5% of this market. That concentration tells an uncomfortable story about access. The WHO notes that diagnostic capacity for pulmonary testing remains severely inadequate across much of sub-Saharan Africa, South Asia, and parts of Latin America — regions where, paradoxically, occupational lung disease from mining, textile work, and biomass cooking fuels is most prevalent. Nearly 90% of COPD deaths among people under 70 occur in low- and middle-income countries, yet the equipment that might identify the disease early is concentrated in wealthier hospital systems thousands of miles away.

The economic case for portable, lower-cost gas exchange devices in emerging markets is strong. Whether manufacturers move aggressively into those markets — or wait until established markets plateau — will likely define which companies lead the next decade of this space. The technology to serve those populations already exists. The commercial will to build distribution infrastructure for it is still forming. That gap, more than any product innovation, may determine how many of those invisible millions eventually get diagnosed before their condition becomes irreversible.