Company Description Guardant Health is a leading precision oncology company focused on guarding wellness and giving every person more time free from cancer. Founded in 2012, Guardant® is transforming patient care and accelerating new cancer therapies by providing critical insights into what drives disease through its advanced blood and tissue tests, real-world data and AI analytics. Guardant tests help improve outcomes across all stages of care, including screening to find cancer early, monitoring for recurrence in early-stage cancer, and treatment selection for patients with advanced cancer. For more information, visit guardanthealth.com and follow the company on LinkedIn , X (Twitter) and Facebook . Department Summary The Technology Development Department is responsible for developing, validating, implementing, and maintaining the tests used by Guardant Health for cancer detection. This role sits in Sustain & Support (S&S) within Technology Development, partnering tightly with Clinical Operations to triage and resolve clinical failures, develop and improve reagent QC systems to reduce recurring failures, and optimize on-market liquid and tissue assays under regulated quality systems. Within S&S, we optimize deployed methods when quality issues arise, develop PQ strategies, scale manufacturing processes, and drive sustaining projects under design control. This team operates at the intersection of assay, bioinformatics, operations, and quality, serving as the link across functions to sustain robust clinical production. Position Summary The Scientist I in S&S will help ensure the reliability and continuous improvement of Guardant's on-market assays. This role will focus on investigating and resolving failures in clinical laboratory operations, strengthening reagent QC systems to improve consistency and reduce repeat issues, and supporting process validations in compliance with regulated quality systems. The Scientist I will combine wet-lab assay expertise, laboratory and operational data analysis, and structured quality-system investigation to identify root causes, guide corrective actions, and enhance product performance. They will work closely with Clinical Operations, Bioinformatics, Process Engineering, Reagent QC, Manufacturing, and Quality teams to deliver durable fixes, reduce QC failures, and enable efficient technology transfer into production. In addition, the scientist will contribute to NCR and other quality-system investigations, support validation and change-control documentation, and provide ongoing technical support for sustaining and scaling Guardant's assays. Essential Duties and Responsibilities Draft and execute verification and validation protocols, including

IQ/OQ/PQ

activities; contribute to design•and change-control packages and risk assessments; and support manufacturing process validation activities to production-grade standards. Operate and troubleshoot NGS workflows end to end, including sample preparation, library preparation, target enrichment, sequencing, and medium•to high-throughput runs. Operate laboratory automation platforms as applicable and support instrument maintenance, troubleshooting, and defined method improvements. Partner with Technology Development and Bioinformatics to develop, evaluate, and implement assay and process improvements; execute structured transfers into Clinical Operations; and support the clinical laboratory post-transfer through troubleshooting, training, and controlled documentation. Analyze assay, reagent QC, sequencing, and clinical operations data by integrating information from SQL databases, flat files, LIMS, and other internal data sources. Use Python and Jupyter to identify trends, test hypotheses, and determine relationships between upstream process variables, QC metrics, and assay failures. Follow FDA and

ISO 13485

quality-system standards and support structured investigations of assay, reagent, and process failures, including root-cause analysis, impact assessment, evaluation of potential corrective actions, and preparation of supporting documentation for NCRs, change controls, audit responses, and related quality records. Maintain complete, GDP-compliant records with full traceability. Present technical findings, conclusions, limitations, and risk-benefit tradeoffs to laboratory leadership, Bioinformatics, Process and Manufacturing Engineering, and Clinical Operations; write clear technical reports; and support cross-functional decision-making. Work location requirement : This role requires the employee to work onsite at both the Redwood City and Palo Alto offices, based on business needs. Qualifications PhD in Molecular Biology, Genomics, Biochemistry or related field, or equivalent work experience. A minimum of 0-2 of related experience (post-doctoral research or relevant industry experience will be considered) Strong foundation in molecular biology, including experience with NGS library preparation and target enrichment. Familiarity with circulating cell-free nucleic acid workflows is a plus. Experience operating NGS instruments and executing sample-preparation assays in medium•or high-throughput environments. Experience with process automation or liquid-handling platforms is preferred but not required. Strong data-analysis skills using Python and Jupyter for scripting, automation, and visualization, with the ability to work across SQL tables, flat files, LIMS, and other laboratory data sources. Experience analyzing assay, reagent QC, operational, or sequencing datasets is strongly preferred. Familiarity with NGS bioinformatics outputs is an advantage. Experience designing, executing, or analyzing structured scientific studies, with strong technical documentation and report-writing skills. Experience with verification, validation, manufacturing process studies, or SOP/Work Instruction authorship is preferred. Excellent cross‑discipline communication and a track record of independent and team‑based problem solving in fast‑paced environments. Strong organization, attention to detail, and commitment to good documentation practices (GDP). Experience working under structured laboratory or quality-system requirements, with an understanding of controlled documentation, traceability, deviation investigation, and change management. Experience in FDA• CLIA• or ISO 13485-regulated environments is preferred. AI & Digital Fluency Demonstrate curiosity, sound judgment, and the ability to critically evaluate and responsibly leverage AI-enabled tools in accordance with company policies, ethical standards, and regulatory requirements to improve the efficiency, effectiveness, and quality of work.

Hybrid Work Model:

This section is applicable to onsite employees who are eligible for hybrid work location as specified by management and related policies. Guardant has defined days for in-person/onsite collaboration and work-from-home days for individual-focused time. All U.S. employees who live within 50 miles of a Guardant facility will be required to be onsite on Mondays, Tuesdays, and Thursdays. We have found aligning our scheduled in-office days allows our teams to do the best work and creates the focused thinking time our innovative work requires. At Guardant, our work model has created flexibility for better work-life balance while keeping teams connected to advance our science for our patients. The annualized base salary ranges for the primary location and any additional locations are listed below. This range does not include benefits or, if applicable, bonus, commission, or equity. Each candidate's compensation offer will be based on multiple factors including, but not limited to, geography, experience, education, job-related skills, job duties, and business need.

Primary Location:

Redwood City, CA Primary Location Base Pay Range:

$115,200•$158,400 Other US Location(s)

Base Pay Range:

$97,920•$134,640 If the role is performed in Colorado, the pay range for this job is: $103,680•$142,560 Employee may be required to lift routine office supplies and use office equipment. Majority of the work is performed in a desk/office environment; however, there may be exposure to high noise levels, fumes, and biohazard material in the laboratory environment. Ability to sit for extended periods of time. Guardant Health is committed to providing reasonable accommodations in our hiring processes for candidates with disabilities, long-term conditions, mental health conditions, or sincerely held religious beliefs. If you need support, please reach out to Peopleteam@guardanthealth.com A background screening including criminal history is required for this role. GH will consider qualified applicants with criminal arrest or conviction histories in a manner consistent with applicable law including but not limited to the LA County Fair Chance Policies and the Fair Chance Act (Gov. Code Section 12952). Guardant Health is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability. All your information will be kept confidential according to EEO guidelines. To learn more about the information collected when you apply for a position at Guardant Health, Inc. and how it is used, please review our Privacy Notice for Job Applicants . Please visit our career page at: http://www.guardanthealth.com/jobs/