Reimbursement Policy Changes: Exagen's revenue heavily depends on third-party payor coverage and adequate reimbursement rates for its diagnostic tests. Any adverse changes in Medicare, Medicaid, or private insurance policies, including rate reductions or coverage restrictions, could significantly impact financial performance and market access.

Intense Competition in Diagnostics: The diagnostic market, particularly for autoimmune diseases, is highly competitive. Exagen faces challenges from established diagnostic companies, new entrants, and academic institutions developing similar or superior tests, potentially leading to price pressure, loss of market share, and reduced test volumes.

Limited Clinical Adoption of Tests: Despite the medical value of its tests, widespread adoption by physicians may be slow. Factors such as physician unfamiliarity, resistance to changing diagnostic protocols, lack of strong clinical guidelines endorsement, or insufficient evidence of clinical utility could hinder test utilization and revenue growth.