A Cambridge start-up has pulled off something British hardware firms are rarely credited with: persuading investors to write a large cheque for a physical device in an age obsessed with software.
TidalSense has raised £14.2 million to roll out a handheld test that diagnoses a killer lung disease in five minutes rather than the best part of an hour. The round, led by North American impact fund Cross Border Impact Ventures alongside returning backers BGF, Airstream Capital and Foresight Group, will fund the test’s rollout across the NHS, a commercial push into Europe and entry into the US market. Some will go towards software that diagnoses asthma using the same device.
The device tests for chronic obstructive pulmonary disease (COPD), which the NHS ranks as the third most common cause of death in England, killing 30,000 people a year and costing the health service £1.9 billion. Patients breathe normally into the handheld unit for 75 seconds, and a set of AI models trained on more than 2.5 million breaths returns a diagnosis on screen.
For clinicians, the gain is throughput. The device lets them see up to six patients an hour, against about one with traditional spirometry, a test whose spirometer was invented in 1846 and still demands forceful exhalation and specialist training. Any healthcare professional can be trained to use the new device in ten minutes.
“A patient will breathe normally through it for 75 seconds,” said chief executive Ameera Patel. “It’s processed in real time and the clinician gets a diagnosis on the screen. That, end-to-end, is as little as five minutes, so it’s a pretty radical change in time.”
Patel, who trained as a medical doctor before a PhD in applied maths and computational neuroscience, is blunt about the condition’s reputation. “The really big misconception is that [COPD] is a smoker’s disease, which it isn’t,” she said. “If you look at most of the rest of the world, one of the biggest drivers is indoor cooking with biomass fuel and a quarter of cases are actually caused by air pollution.”
The commercial case rests on reaching patients earlier. The software, N-Tidal Diagnose, exceeded 90 per cent accuracy in its first real-world trial in 2023 and launched in the NHS last year, and is now used across Suffolk, northeast Essex, Wales, Glasgow and community lung screening clinics in southern England. It matters because a quarter of COPD patients wait five or more years for a diagnosis, according to Asthma + Lung UK.
For UK founders, though, the sharper lesson is in how the money was raised. Patel said the environment had become “more difficult” for early-stage companies, with rounds taking longer to close as investors turn risk-averse. Where many read that as a reason to avoid capital-hungry hardware, she argues the reverse.
“Hardware companies are underinvested in,” she said, “but my personal view is that they are some of the most defensible now given how easy it is to build software products with AI.”
It is an argument with resonance well beyond respiratory medicine. Cambridge has long produced world-class science while struggling to turn spin-outs into global businesses, and TidalSense joins other Cambridge diagnostics ventures chasing growth capital in a market now writing fewer, larger cheques.
Founded in 2013 by chief engineering officer Julian Carter, who holds a PhD in microelectronics and more than 35 years developing medical devices, the company has spent over a decade on the device. The latest round takes its total raised to nearly £30 million, including £8 million in grant funding. In a market that increasingly rewards a defensible moat, a physical device built on a decade of proprietary data may prove exactly that.
