He left Wall Street to sell a cancer test that starts at home. The pitch was almost embarrassingly simple: make it easy enough that people actually take it.
A stranger skipped her colonoscopy. Years later, that decision became a company.
Andrew Barnell runs a diagnostics company with his sister. She is the doctor. He is the one who knows what a term sheet looks like. Between them sits Geneoscopy, a St. Louis life sciences company built around a stubbornly human insight: the best medical test in the world is worthless if the patient never takes it.
That is the whole bet. ColoSense, the company's flagship product, is a noninvasive stool test that screens for colorectal cancer and advanced adenomas using RNA biomarkers. In 2024 it became the first multitarget stool RNA test of its kind to win FDA approval. Barnell, as CEO, is the person who got it there.
The idea did not come from Andrew. It came from his sister, Erica Barnell, during her first clinical rotation while earning an MD and PhD at Washington University School of Medicine in St. Louis. She met a woman with Stage IV colorectal cancer who had never had a colonoscopy. The reason was not denial or fear of bad news. It was inconvenience. The procedure was too much of a burden, so she skipped it, and by the time anyone looked, it was too late.
Colorectal cancer is one of the most preventable cancers there is. Caught early, it is highly treatable. The problem has never really been the biology. It has been the friction - the prep, the time off, the indignity, the appointment that keeps getting pushed. Erica saw a science problem wrapped inside a behavior problem. Andrew saw a market.
So the siblings split the labor along the obvious line. Erica took the science and became Chief Medical and Science Officer. Andrew took the business and became CEO. The division of labor is so clean it sounds like a joke, but it is the actual operating structure of the company.
Series C investors included Bio-Rad Laboratories, Petrichor, Labcorp, Morningside Ventures, Lightchain Capital, Mercy Health and others.
Barnell did not arrive at biotech the usual way. He studied applied economics and management at Cornell, with a specialization in finance. He earned an MBA from The Wharton School in health care management and entrepreneurial management. His first job was as a financial analyst in J.P. Morgan's healthcare investment banking group, where he worked on mergers, acquisitions and capital markets deals. After that came private equity, as an associate at Lindsay Goldberg, a middle-market firm that partners with family-owned businesses.
It is a resume built for buying and selling companies, not founding one. But there is a logic to it. Diagnostics is a business where the science is necessary and the commercialization is everything. Plenty of brilliant tests die in the gap between the lab and the patient because nobody could fund the trials, navigate the FDA, or convince payers to reimburse. Barnell spent his early career learning exactly that gap. Then he built a company to live inside it.
B.S., Applied Economics & Management, finance specialization.
MBA, Health Care Management and Entrepreneurial Management.
Healthcare investment banking, then middle-market private equity.
Stool-based cancer screening was not new when Geneoscopy showed up. The established players looked for DNA signals shed by tumors. Geneoscopy made a different technical bet: RNA. The company's patented platform reads multitarget stool RNA - what the field abbreviates as mt-sRNA - to flag colorectal cancer and the advanced adenomas that precede it.
RNA is a moving target where DNA is a fixed one. It reflects what cells are actively doing, not just what they are. That is harder to measure and, the company argues, richer in signal. The FDA approval in 2024 was the validation of a years-long contrarian wager that the harder signal was the better one.
Securing FDA approval for ColoSense marks a significant milestone and demonstrates that our patented RNA technology can provide millions of eligible adults with a safe and effective option for detecting CRC and advanced adenomas.
This achievement is a testament to our deep dedication and commitment to bringing innovative technology to market that will improve outcomes for this deadly, yet preventable, disease.
We wanted to make the test extremely easy.
Barnell is a regular on healthcare stages and investor floors. A few places to hear him explain ColoSense and the company in his own words.