Sr. Data Scientist, Assay Development

About Us   DELFI Diagnostics, Inc. (DELFI Diagnostics) is developing next-generation, blood-based tests that are reliable, accessible and deliver a new way to help detect cancer. Employing advanced machine-learning methods to whole-genome sequencing data, the DELFI ("DNA EvaLuation of Fragments for early Interception") platform is built to address the highest-burden health challenges. DELFI Diagnostics prioritizes solutions that have the potential to save lives on a global scale, including for historically underserved populations. DELFI Diagnostics’ platform relies on fragmentomics – the discovery that cancer cells are more chaotic than normal cells and, when they die, leave behind tell-tale patterns and characteristics of cell-free DNA (cfDNA) fragments. FirstLook Lung, for individuals eligible for lung cancer screening, is DELFI Diagnostics’ first laboratory-developed screening test and can be part of routine blood work. FirstLook Lung uses millions of data points to reliably identify individuals who may have cancer detected through low-dose CT, including early stage disease with a negative predictive value of 99.8 percent. This test has not been cleared or approved by the FDA.   In our passionate pursuit to radically improve health outcomes, we serve humanity when we:   Lead with Science, Anchor in Pragmatism: We pioneer life-changing science by ensuring quality, transparency, and rigor at all times. We explore thoughtfully, experiment smartly, and deliver impact with conviction.   Build With & For All: We embrace diverse backgrounds to innovate and achieve together. We are not just building a product - we aim to disrupt the path of cancer for all - no matter geography or socioeconomic class    Put We over I: We are a home for high-performing people. Through teamwork, we build collective intelligence. Each of us wins when those we serve and those who serve with us--win. We show up with empathy, humility, and integrity at every step of the journey.   DELFI has 1-2 designated in-office working days each week for employees who live within within 50 miles of Palo Alto, CA  About the Role

The Senior Data Scientist will collaborate with a cross-functional team of laboratory scientists, clinicians, engineers, and other data scientists to develop statistical analysis methods supporting early cancer detection assays. This role spans assay development, analytical validation, and QC and control strategy, contributing to products advancing through verification, validation, and regulatory submission toward clinical use. The ideal candidate brings strong foundations in probability theory and statistics, applied experience in a regulated diagnostics or similarly rigorous data environment, and the ability to translate complex analyses into clear documentation for cross-functional and regulatory audiences.

What You'll Do

Design and execute analyses supporting assay development, analytical validation, and QC and control strategy, applying statistical methods appropriate to regulated diagnostic development

Collaborate cross-functionally with assay development, lab operations, and software teams to design experiments, interpret results, and produce documentation meeting quality system and regulatory standards.

Contribute statistical and data science expertise to control strategy development, including qualification and monitoring frameworks for reagents, instruments, and sample level QC.

Provide operational data science support for production and LDT/IVD run monitoring, including troubleshooting assay performance issues, trending QC metrics, and supporting root cause investigations.

Produce high quality Python code following best practices established by the software development team.

Support regulatory submissions (CLIA/CAP, NYS, FDA as applicable) with rigorous, well documented analysis.

What You'll Bring

Required

Master's degree in Applied Math, Statistics, Bioinformatics, Engineering, or a related quantitative field; PhD preferred.

Five or more years of practical experience in scientific or mathematical data analysis, with at least three years in Python (numpy, pandas, and similar).

Strong foundations in probability theory and statistics, including hypothesis testing, confidence intervals, parameter estimation, and variance components.

Experience working in a regulated diagnostics environment (IVD, LDT, or similar), including designing and executing rigorous studies and analyses and documenting them appropriately.

Ability to connect assay chemistry to data behavior, applying this understanding to troubleshoot assay performance issues.

Preferred

Exposure to NGS based assay development, including familiarity with sequencing data QC and batch level variability.

Experience analyzing high dimensional genomic or molecular data.

Familiarity with common machine learning techniques and practical experience with implementation and validation.

Familiarity with Design of Experiments and related quality methodologies (measurement systems analysis, control charts, Six Sigma/DMAIC).

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.