“He told me stories of his patients literally dying because he couldn't get the diagnostics results back fast enough to figure out how to treat them,” recalled Miriam Huntley (GSAS ’16), reflecting on one of her first conversations with Doug Kwon (College ’93, HMS ’07).
The two spoke at length about the tragic consequences of slow diagnostics for infectious diseases and wondered whether genetic sequencing could pave the way for a new generation of faster, more precise tests.
At the time, Huntley had been leveraging sequencing as part of her PhD studies. “It seemed like an obvious tool that we could use to radically improve infectious disease diagnosis, but there was nobody working on it,” she said.
Huntley and Kwon began developing the next generation of diagnostics in 2015, along with scientific co-founders Melis Anahtar (HMS ’17) and Dougal Maclaurin (GSAS ’16). Soon after, Kwon convinced his former college roommate, Jong Lee (College ’93, HBS ’99), to join them. This set them on a 10-year journey to launching the startup Day Zero Diagnostics, achieving scientific breakthroughs, raising tens of millions of dollars in grant and venture funding, and ultimately being acquired by multinational biotechnology company bioMérieux in 2025.
Recently, Huntley and Lee spoke with the Harvard Innovation Labs about how they started and scaled Day Zero Diagnostics, the impact they’ve had in the field of diagnostics, and the startup lessons they learned over the last decade.
Leveraging Harvard University resources to launch and grow
When Huntley and Kwon needed a place to meet and work on their idea in the summer of 2015, they decided to go to the Harvard Innovation Labs. “We were really lucky to have that as a place to work and eventually got accepted into one of the i-lab's startup programs. And when we grew, we applied for the [Pagliuca] Harvard Life Lab. It was such a great place to work, with great community.”
Lee, who initially joined as an advisor, encouraged them to enter business plan competitions. “The funding we received from those competitions, coupled with the support we received from the i-lab, led us to spin out our work as a real company,” said Lee.
Leveraging the Harvard Innovation Labs for advising, co-working space, and cloud computing credits allowed Day Zero Diagnostics to operate leanly as they worked on the research necessary to raise venture funding. Lee elaborated, “For six months of 2016, we were paying just $200 per month for DZD because we had the support of the i-lab, and were taking advantage of every free startup resource at the time, from the i-lab's AWS Credits to $100,000 worth of additional cloud credits we won in a business plan competition.”
Setting the company’s trajectory with a single decision
In 2016, Day Zero Diagnostics made a decision that would define the company’s future: choosing to focus on a better diagnostic for sepsis as a result of bloodstream infections. Huntley explained, “The reason we picked sepsis was because of the very high unmet clinical need. But this choice came with a number of very steep technical challenges.”
Lee and Huntley explained that blood was the hardest sample type that DZD could have picked, and it set them on a path of “essentially becoming two startups in one,” according to Lee. First, DZD set up a wet lab company focused on achieving scientific breakthroughs necessary to recover pathogens whole genomes directly from blood, a challenge complicated by the vastly greater abundance of human DNA in the sample and the high concentration of natural inhibitors that block molecular reactions. Second, the startup built a computational team to develop AI for analyzing the sequencing data, with the goal of providing a fast and accurate diagnosis and predicting what antibiotics would be effective for the infection and which would not.
Achieving a scientific breakthrough
One of the greatest scientific challenges that Day Zero Diagnostics worked on for multiple years was enriching blood samples to a level that would allow them to find and sequence bacterial DNA within a “sea of human DNA that outnumbers it at a ratio of a billion to one.”
Lee shared, “We were pioneers in both the [wet lab] and [AI] domains and were creating methods for being able to do things that no other diagnostics company in the world had been able to do.”
Shortly after receiving a top prize in the 2020 Harvard President’s
Innovation Challenge, DZD achieved a significant scientific breakthrough
on the sample enrichment side. They successfully enriched the ratio of
bacterial DNA to human DNA in blood samples by 10 orders of magnitude,
or "logs". In other words, DZD’s methods were able to increase the
relative concentration of the tiny amount of bacterial DNA by a factor
of 10 billion. According to Lee, “The next closest enrichment in the
published world was about three logs.” This breakthrough paved the way
for their innovative sequencing-based solution.
Reaching a multi-million-dollar acquisition
In early 2025, as the company was completing an end-to-end prototype of the diagnostic system, Lee decided that the best path forward to continue advancing the technology would be to get acquired by a large, strategic player. In June, DZD completed a $25 million sale to bioMérieux, a prominent, multinational diagnostics company that wanted to make DZD’s important work the center of their future sequencing business.
In explaining how they were able to run a successful exit during a year when many biotech startups had to shut down because of the private and government funding landscape, Lee explained that a lot of the largest companies in their industry had followed the company for years and had already done deep diligence on DZD during previous funding rounds. “From their prior diligence, they had a lot of confidence in the representations we made about the technology and what it was capable of,” he said.
When announcing the acquisition, bioMérieux committed to developing and using the DZD platform. Céline Roger-Dalbert, bioMérieux’s executive vice president of research and development, had this to say about the acquisition: “Thanks to this strategic acquisition, we will broaden our capabilities in next-generation sequencing (NGS), following a proactive and forward-thinking approach to innovation. Sequencing is a promising technology that offers several advantages. It enables diagnosis to be approached without necessarily having a hypothesis about the causes of infection, and results are obtained more rapidly, which is crucial for the diagnosis of infectious diseases.”
Advising the next generation of entrepreneurs
When asked what advice they’d give to early-stage founders, Huntley stressed the importance of getting customer feedback as early as possible, even if you’re in a highly regulated industry. "It's incredibly energizing to get your product out there…It really increases the speed and focus with which we were able to focus the product,” she said.
Huntley and Lee agreed that it’s also about building a great team that’s truly passionate about the startup they’re working on. “You have to build a team that's mission-oriented...truth-seeking... and is really in it for the right reasons,” said Huntley. “It's not just about people having the skill sets, which is a must, but a team that can really work together and believes in what they're trying to do as a startup.”
Lee added, “We had an exceptionally good group of people who were really trying to think about the company as a whole – do what's right for the company more than what might be best for any individual on the team. We all had a genuine belief that there was an important problem that needed to be solved, and that we were uniquely capable of solving it.”
Additionally, Lee encouraged founders to own their journey and to be selective about the advisors they recruit and pay close attention to.“A lot of advice that’s given to startups can sound right and appealing, but still be wrong for the specific circumstances you are in. Seek out advisors who can help you build the judgement to know what advice applies for the circumstances you are in.”
