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Remove fear
of the unknown


The status quo that makes healthcare expensive, opaque and out of reach for the majority


We’re a precision diagnostics company that quantifies biology to create powerful molecular diagnostics that are extremely accurate and accessible to all.

Our Leadership

Originating from Y Combinator (S17), our team of engineers, scientists and industry experts are redefining healthcare with tools that quantify biology.

Oguzhan Atay, PhD


Oguzhan believes that diagnostics can be made much more powerful, accurate, and affordable if they were engineered to be quantitative. At BillionToOne, Oguzhan helped develop a patent-pending molecular counter platform that increases the resolution of molecular diagnostics by over a thousandfold. He has led BillionToOne through Y Combinator and raised a total of 17.5M in funding including from venture capital funds and investors who previously invested in tech companies such as SpaceX, Box, Spotify, Palantir, Braintree, and biotech companies such as Counsyl, WebMD, and Omada Health. Oguzhan received his PhD from Stanford, where his work was published on the Cover of Cell Systems.

Previously, Oguzhan graduated summa cum laude and Phi Beta Kappa from Princeton University with a Bachelor’s in Molecular Biology and minors in Physics, Computer Science, and Applied Mathematics.

David Tsao, PhD


David believes that applying engineering principles to biology will be transformative for medicine. He is the original inventor of the DNA molecular counting platform at BillionToOne and has presented BillionToOne’s clinical trial results at national medical conferences. David has a bachelor’s degree in Physics, cum laude, from Princeton University with minors in Biophysics and Engineering Management Systems. While at Princeton, he was twice awarded the Shenstone Prize in Physics. He received a PhD in bioengineering from Rice University, where he was awarded a Nanobiology training fellowship.

Nancy Johnson, MT(ASCP)


Nancy has a passion for building and leading commercial sales teams. She believes in the empowerment of individuals to achieve personal and professional goals. Nancy brings more than 20 years of diagnostic sales leadership experience in both start-up and large-scale sales organizations. Nancy joins BillionToOne from Foundation Medicine where she played an instrumental role in the company’s commercial strategy and execution, building and leading her sales team to success. Prior to Foundation Medicine Nancy held several commercial leadership positions at various molecular diagnostic companies. Nancy started her career as a board-certified Medical Technologist and holds a BS in Medical Technology from Creighton University

Shan Riku, MBA


Shan is passionate about launching life-changing products and delivering seamless end-to-end user experience through the products. Shan has 10+ years of experience in launching wide range of products and brands, from online marketplace to cord blood banking and is responsible for all aspects of product at BillionToOne. Shan started her career at McKinsey & Co., where she helped launch two pharmaceutical drugs and a new brand line of high-end audio products for multinational corporations. Shan holds MBA from Stanford University, MPA/ID from Harvard University, and BS in Chemistry and Minor in Biology from Massachusetts Institute of Technology (Phi Beta Kappa).

Brent Kirk


Brent believes that one size does not fit all with hospitals, physicians, and patients. Brent drives our sales strategy and operations teams to ensure customer loyalty while improving the satisfaction of both internal and external partners. An unrelenting executionist, Brent has fiercely loyal customers and has helped multiple startups with hyper-growth plans from series A through IPO. Brent graduated from Arizona and has a history of success in the tech and biotech industry.

Brian Landry, PhD


Brian believes that biomolecules are the engineering tools of the future. Brian has published eight peer reviewed publications in top tier journals and written three patents. Brian was a National Defense Science and Engineering fellow and co-wrote grants that secured over one million dollars in funding during his graduate work. Brian holds a PhD in Bioengineering from Rice University and a BS in Biomedical Engineering from Washington University in St. Louis.

Dominic Weilbaecher


Dominic is an laboratory industry veteran in both Revenue Cycle and Market Access. He has over 15 years of experience with Quest Diagnostics and another 10 years with multiple other esoteric laboratories with a specific focus on bringing new technologies into the commercial marketplace with positive medical policy and value-based reimbursement. Dominic is also well versed in managing all aspects of billing commercially for these tests and has lead numerous billing system implementations while maintaining strict compliance with all state and federal regulations. He has been responsible for executing over 150 payer contracts in his career and has excellent relationships with Senior Level Medical Directors and Contracting personnel with many of the major and large regional Insurers and Payers. Dominic is a native New Orleanian and holds a Bachelor of Science degree in Finance from the University of New Orleans.

Vivek Gandhi, MBA


Vivek loves researching user and business needs and building technology products that are just right for those needs. In the past, Vivek has worked on a wide variety of tech products, including the BREW mobile OS, Kindle Fire tablet, and Google Play store. An engineer by training, Vivek also holds an MBA from UC Berkeley. At BillionToOne, Vivek oversees all our software development activities.



Kitty is a passionate, interdisciplinary diagnostic scientist with experience in R&D and in clinical operations. She began as a R&D chemist at Inova Diagnostics, where she was the primary developer of QUANTA Flash DGP Screen, which received FDA 510k approval. Her experience as a Clinical Laboratory Scientist spans from NIPT at Sequenom, pharmacogenetics at Millennium Health, and cancer diagnostics at Guardant Health. Kitty received her BA in Molecular and Cell Biology from UC Berkeley and clinical training from UC Irvine.

Devon Chandler-Brown, PhD


Devon is passionate about engineering biological systems which he thinks can be leveraged to solve challenges in medicine and improve people’s lives. He earned his PhD in Biology at Stanford University where he authored several peer-reviewed publications and was awarded a Genentech Foundation Predoctoral Fellowship. Previously, Devon graduated with a BS in Biochemistry and Biology from University of Washington.

Alyssa McLemore, CLS, MLS (ASCP)CM


Alyssa is the Clinical Laboratory General Supervisor with over 6 years of experience in high-volume, high complexity clinical laboratories performing novel genomic tests. Alyssa is patient-focused, detail-oriented, and a collaborative team player who reliably goes above and beyond to deliver results. Alyssa received a BS in Biotechnology from the University of California, Davis and graduated from the Clinical Laboratory Science program at San Jose State University.

Anna Rolda, MS, CLS, MLS (ASCPi)CM


Anna is responsible for BTO’s quality and regulatory efforts, ensuring approval and maintenance of licenses needed to operate as a diagnostics company. Anna was a Lab Scientist in Transfusion Medicine and Cellular Therapies for top academic hospitals including Medical University of South Carolina, Tufts Medical Center, Dana-Farber/Harvard Cancer Center, and UCSF. Prior to joining, Anna was a Regulatory Consultant at FibroGen supporting IND and NDA activities on the anemia drug, Roxadustat. Anna holds a BS in Medical Technology from the University of Santo Tomas and an MS in Regulatory Affairs for Drugs, Biologics, and Medical Devices from Northeastern University.

Sharon Ricafrente, CLS, MLS (ASCP)CM


Sharon believes in helping patients make the right decisions about their health with her work as a Clinical Lab Scientist. Sharon has over 10 years of experience in both the hospital setting and biotech industry having worked at Stanford University Medical Center, Kaiser Permanente, Genomic Health and Guardant Health. Prior to joining BillionToOne, Sharon was the Clinical Operations Supervisor at Guardant Health who helped build the Clinical Lab and grow the Operations team from a staff of 10 to over 60 team members. Sharon holds a BS in Biological Sciences from California State University-East Bay and graduated from the Clinical Laboratory Science Program at San Jose State University.

Patrick Ye, PhD


Patrick knows that molecular biology can be harnessed to overcome previously unsolved challenges in molecular diagnostics to impact people’s lives. Patrick earned his PhD in Bioengineering from Stanford University, during which he authored several peer-reviewed publications. A truly interdisciplinary scientist and engineering, Patrick received a Stanford Interdisciplinary Graduate Fellowship and was named a Siebel Scholar.

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