BillionToOne Is Solving One of Biotech’s Hardest Problems

Why It Matters

By turning ultra‑low‑frequency DNA signals into actionable diagnostics, Billion to One accelerates universal prenatal screening and promises earlier, less invasive cancer detection, reshaping patient outcomes and creating a multi‑billion‑dollar market opportunity.

Key Takeaways

• Billion to One's prenatal test processes over 600,000 samples annually.
• Synthetic DNA tags reduce amplification noise, enabling needle‑in‑haystack detection.
• Company expanded from $300k seed to $4 billion valuation in under a decade.
• New ultra‑sensitive MRD test aims for early‑stage cancer detection.
• Interdisciplinary teams accelerate product development and scale to 2 million tests.

Summary

Billion to One is redefining molecular diagnostics by turning the needle‑in‑a‑haystack problem of rare DNA fragments into a tractable mathematical one. Its flagship prenatal test, now processing more than 600,000 samples a year and holding roughly 20% of the U.S. market, uses synthetic DNA barcodes—quantitative counting templates—to measure and subtract amplification errors, delivering reliable detection of single‑base‑pair mutations from maternal blood.

The company’s core technology, built by two PhD students in a shared lab bench with $300,000, has scaled dramatically: a public listing valued at over $4 billion, a state‑of‑the‑art automation line that can handle up to 2 million tests annually, and an AI‑driven accessioning system that logs samples in 60 seconds. Leveraging the same platform, Billion to One launched a liquid‑biopsy cancer test in 2023 and is now finalizing an ultra‑sensitive minimal residual disease (MRD) assay that could detect stage‑one cancers before they manifest clinically.

Founders Ogazan and David emphasize the interdisciplinary blend of chemistry, bioinformatics and machine learning that made the breakthrough possible. A poignant patient story illustrates the impact: a 40‑year‑old with metastatic colorectal cancer, deemed hospice‑bound, received immunotherapy after the company’s blood test identified microsatellite instability missed by tissue biopsy, leading to a dramatic tumor response. Their narrative underscores the clinical relevance of detecting tumor DNA in circulation.

If successful, the MRD test would represent the “holy grail” of oncology—early, non‑invasive cancer detection—potentially reshaping screening protocols and expanding the market beyond prenatal care. The company’s rapid commercialization, aggressive sales strategy, and focus on interdisciplinary talent suggest it will continue to disrupt both genetic screening and oncology diagnostics, driving broader adoption of liquid‑biopsy technologies.

Original Description

1 in 11 babies born in America this year will be screened by a genetic test that didn't exist a decade ago.

Biotech startup BillionToOne turned a simple but radical idea—detecting rare fragments of fetal DNA in a mother's blood—into one of the most widely used prenatal tests in the U.S. And they're not stopping there. The same approach could unlock something even bigger: early-stage cancer detection from a blood test, a breakthrough that could one day save millions of lives.

In this episode of Hard Tech, YC's Jared Friedman sits down with David Tsao and Oguzhan Atay to hear how they went from half a lab bench to a $4B biotech company—and why they believe this is just the beginning of what their technology can do.

Learn more: https://www.billiontoone.com

Chapters:

00:00 – Finding One Mutation in Billions

01:00 – Detecting Disease From a Blood Sample

02:10 – From Lab Idea to $4B Company

03:05 – The Breakthrough That Made It Possible

05:15 – Building the First Test From Scratch

07:30 – One Customer and a Sales Crisis

08:55 – Inside the Lab: How It Actually Works

12:10 – Detecting Cancer From Blood

13:50 – The Path to Early Cancer Detection

16:05 – Why Early Cancer Detection Is So Hard

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