BillionToOne develops proprietary single-molecule next-generation sequencing diagnostic tests powered by Quantitative Counting Templates that detect sparse genetic targets in cell-free DNA with superior sensitivity compared to traditional methods. The company operates two core business lines: prenatal non-invasive testing products that assess fetal risk for recessive genetic conditions, chromosomal abnormalities, and blood type compatibility; and oncology liquid biopsy tests that detect actionable tumor mutations for therapy selection and quantify tumor burden for treatment response monitoring. BillionToOne commercializes these laboratory-developed tests through direct sales to obstetricians and oncologists in the United States, generating revenue from insurance reimbursement, government programs, and patient payments, with expanding coverage from major payors and favorable reimbursement rates.