Greg O’Grady: The Surgeon Who Left Surgery to Map the Stomach

“Just like the heart, the stomach has its own electrical activity that controls it,” Greg O’Grady told the New Zealand tech site theBit in 2021. “But it’s a lot more difficult than with the heart… the signals are 100 times weaker.” That sentence contains most of the career of a man who trained as a surgeon, spent years in a bioengineering lab, and in 2021 walked away from the operating theatre to build a company around those faint signals. The company is Alimetry, a University of Auckland spin-out, and its product, Gastric Alimetry, is a wearable test that maps the stomach’s electrical rhythm through the skin. It is now in use in the United States, the United Kingdom, Australia and New Zealand, and this month the FDA cleared it again, for the sixth time.

The surgeonPatients without answers

O’Grady is a Professor of Surgery at the University of Auckland, a trained general and colorectal surgeon with a PhD in surgery and bioengineering, and the problem he set out to solve is one he met in clinic. “My background is in surgery, and I’ve seen many patients over the years, but we just can’t get an explanation for their symptoms,” he told the New Zealand Herald. “So there’s a huge need for a better way to diagnose gut problems.” The scale of it is what drove him. “About one in five people carry around with them some chronic abdominal complaints and the diagnostics for them at the moment are very poor,” he told UniServices, the university’s commercialisation arm. “Many tests are inconclusive and a lot of patients end up with no real answers.”

His way of explaining the gap is one of the clearest in gastroenterology. “Imaging people with an X-ray, or examining their abdomen, or putting an endoscope down them – those don’t answer questions of function, they answer questions of structure,” he said. “And so what we’ve developed is a test of function.” A scope can find an ulcer. It cannot tell you whether the muscle of the stomach is keeping time. For people with chronic nausea, vomiting, early fullness or pain after eating, including many living with gastroparesis, that second question is often the one that matters.

The labProducts instead of papers

After training as a surgical fellow in Auckland and Australia, O’Grady came home in 2017 and found himself restless. “I started to feel a bit dissatisfied with publishing results in engineering journals about medical devices but not having them go anywhere,” he said. “So I pitched this idea to the University that I would start a surgical engineering lab where we would develop products instead of papers.” The idea that became Alimetry came out of that work with the bioengineer Dr. Armen Gharibans, his co-founder, who built a prototype array in 2019. When its readings lined up with patients’ symptoms, O’Grady says, the decision made itself. “Seeing that data was the moment of knowing we had to pursue this – not just making a research tool but a product.”

Building a company meant giving something up. In 2021 he stepped away from surgery and cut his university role to part time. “It was an extremely difficult decision to make because I love surgery and trained for a long time to do it,” he said, “but I felt like I had to follow these opportunities.” His reasoning is worth reading in full. “If you’ve got an invention that can make a meaningful difference to patients, you have to take that further and build it into a product so people can use it. And the painful journey of building a product and company requires a champion, and ultimately if it’s your baby, that has to be you.”

The testSixty-four electrodes and a meal

The test itself is gentle by gut-diagnostics standards, which is part of the point. A patient wears a single-use adhesive array of 64 electrodes across the upper abdomen, connected to a small reader, and logs symptoms on a tablet through about four and a half hours: a fasting baseline, a standard meal, then four hours of recording as the stomach gets to work. There is no tube, no scope and no radiation. That matters most for children and teenagers, and the FDA extended the test’s clearance to patients aged 12 and older in 2024. “Parents then don’t have to go through the stress of putting their children under anaesthesia to have a scope or expose them to radiation when they’re still growing,” O’Grady told ACS Information Age.

The regulatory record is steady. The FDA first cleared Gastric Alimetry in June 2022, as a device to record and process the stomach’s electrical activity “as an aid in the diagnosis of various gastric disorders.” Later clearances added symptom-correlation reports, the adolescent indication and, in December 2025, an AI filter that strips out noise from movement. A sixth clearance followed on September 4 this year; the company has not yet said what it covers. Alimetry has raised NZ$16.3 million in a 2022 Series A led by Movac and US$18 million in 2024 in a round led by GD1 with the American Gastroenterological Association’s GI Opportunity Fund and Olympus’s venture arm among the investors. In 2022 the project won the KiwiNet Breakthrough Project Award. “As we discover new features, we put them through the FDA as soon as possible, then make them into the product,” he told TechCrunch. “And we’re definitely not done.”

The evidenceWhat the maps have shown so far

The research is substantial for a company this young, and O’Grady discloses his stake in every paper. A 2022 study in Science Translational Medicine compared 43 people with chronic nausea and vomiting with 43 healthy controls and found two broad groups: about three in ten had clearly abnormal stomach rhythms whose measures tracked their symptoms, while most had normal maps and more anxiety and depression, pointing toward the gut-brain side of the picture. A 2024 study in the American Journal of Gastroenterology ran the test alongside the standard gastric emptying scan in 75 patients: the scan flagged an abnormality in 23 percent, Gastric Alimetry in 33 percent, and the two together in 43 percent, and the new test’s results lined up better with how patients felt. In July, O’Grady was senior author on the Auckland Classification, a consensus framework for sorting these rhythm patterns agreed by a working group of experts from 13 countries. “Its arrival signals a move from symptom labels and guesswork to precision care,” he said, “hopefully bringing new clarity to patients who desperately need solutions.”

The honest next step is outcomes. Most of the published work comes from the company and its founders’ research groups, and no randomized trial has yet shown that testing with Gastric Alimetry leads to better treatment decisions or better health, which is the kind of evidence insurers look for. The test has had its own US billing code since July 2024, but that code does not guarantee payment, and at least one major insurer, Aetna, still lists the test as investigational. O’Grady is candid about the size of the problem. “We don’t have all of the answers within that category,” he said. “That’s the way it is with the gut. It’s a pretty complex system, but we know that there’s a very large number of patients within that functional group who we can significantly help.” For the many people told their scans are normal while they still feel unwell, a test that can show what their stomach is actually doing is a genuinely hopeful thing.

The disclosure mapWhere his interests sit

O’Grady co-founded Alimetry, is its chief executive and a director, and holds a stake in it; he is an author on most of the studies described here and discloses that in each one. He is also a director of a second university spin-out, The Insides Company, and since December 2025 has sat on the board of New Zealand’s Institute for Advanced Technology. Gastric Alimetry is a prescription test ordered by clinicians and cleared by the FDA as an aid to diagnosis, not a standalone diagnosis or a guide to treatment; hospital and patient numbers in company materials are the company’s own. Anyone with ongoing stomach symptoms should start with their own doctor. Gut Health Times has no commercial relationship with Alimetry. This profile is educational, is not medical advice, and was prepared without input from the company.