The Cambridge startup has pulled off something that British hardware firms are rarely called upon to do: persuading investors to write a big check for a mobile device in a software-busy era.
TidalSense has raised £14.2 million to develop a hand-held test that diagnoses fatal lung disease in five minutes rather than the best half of an hour. The round, led by North American impact fund Cross Border Impact Ventures and returnees BGF, Airstream Capital and Foresight Group, will fund the rollout of the test across the NHS, a commercial drive to Europe and entry into the US market. Others will go to asthma monitoring software using the same device.
The device tests for chronic obstructive pulmonary disease (COPD), which the NHS ranks as the third leading 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 the screen.
For doctors, profit is the result. This system allows them to see up to six patients per hour, against one with traditional spirometry, a test that was invented by the spirometer in 1846 and still requires strong inspiration and special training. Any healthcare professional can be trained to use the new device in ten minutes.
“The patient will breathe normally within 75 seconds,” said CEO Ameera Patel. “It’s processed in real time and the doctor gets the diagnosis on the screen. That, in the end, takes five minutes, so it’s a very big change in time.”
Patel, who trained as a doctor before earning a PhD in applied mathematics and computational neuroscience, is unrepentant about the status quo. “That’s a big misconception [COPD] tobacco disease, which is not,” he said: “If you look at most of the world, one of the biggest drivers is cooking at home with biomass fuel and a quarter of the cases are actually caused by air pollution.”
The business case depends on reaching patients early. The software, N-Tidal Diagnose, exceeded 90 per cent accuracy in its first real-world trial in 2023 and was introduced to the NHS last year, and is now being used across Suffolk, north-east Essex, Wales, Glasgow and community lung screening clinics in the south of England. It’s important because a quarter of COPD patients wait five years or more to be diagnosed, according to Asthma + Lung UK.
However, for UK founders, the sharpest lesson is how the money was raised. Patel said the environment has become “very difficult” for emerging companies, with rounds taking longer to close as investors turn to risk. Where many read that as a reason to avoid cash-hungry hardware, he argues the opposite.
“Hardware companies have invested well in them,” he said, “but my personal opinion is that some of the things that can be secured now are given how easy it is to build software products with AI.”
It is an argument that has resonance 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 chasing growth capital in a market now writing fewer, bigger checks.
Founded in 2013 by senior engineering executive Julian Carter, who has a PhD in microelectronics and over 35 years developing medical devices, the company has spent more than a decade in the process. The latest round takes its total raised to nearly £30 million, including £8 million in equity funding. In a market that increasingly prizes a secure channel, a portable device built on ten proprietary data sources may prove just that.
