Exagen Announces Publication of Systematic Review Confirming Robust Real-World Performance of AVISE Lupus

Uniquely identified ~25% of the SLE patients who would otherwise be missed by conventional markers

Demonstrated superior diagnostic accuracy compared with conventional testing, supporting earlier, more definitive diagnosis

Performed consistently across more than 1,200 SLE patients and 14 medical centers, expanding on the original clinical validation

CARLSBAD, Calif., June 01, 2026 (GLOBE NEWSWIRE) -- Exagen Inc. (NASDAQ:XGN), a leading provider of autoimmune testing solutions, today announced the publication of a new systematic review demonstrating that the AVISE Lupus algorithm delivers markedly superior diagnostic accuracy and consistency across patient populations compared with conventional serologic tests alone. AVISE Lupus' enhanced sensitivity and specificity address key diagnostic gaps, supporting an earlier, more definitive Systemic Lupus Erythematosus (SLE) diagnosis, with the potential for earlier intervention, prevention of organ damage and improved long-term outcomes.

"This publication reinforces Exagen's powerful and durable competitive moat – AVISE Lupus routinely demonstrates leading SLE diagnostic performance," said John Aballi, President and CEO. "Built on more than a decade of evidence and over 1,200 SLE patients across leading academic medical centers, the study represents one of the most extensive evidence-generation efforts behind any lupus diagnostic and sets a new standard for rigor in the category. With more than 1 million patients tested since AVISE Lupus launched in 2012, this publication further strengthens our real-world evidence base, supporting our premium market position, reimbursement strategy and broader adoption. Exagen has built a platform that consistently outperforms the standard of care, positioning us to expand our leadership in autoimmune diagnostics."

The paper, titled "Clinical Utility of a Multianalyte Lupus Risk Score Incorporating Cell-Bound Complement Activation Products: A Systematic Evaluation," was published in Lupus Science & Medicine. The analysis consolidated biomarker data for 3,132 individuals from 14 academic medical centers in studies conducted between 2011 and 2025 and found that AVISE Lupus performed strongly across patient populations and uniquely identified 25% of patients otherwise missed by conventional serologies, including anti-dsDNA, anti-Smith, and complements C3 and C4.

"Our findings show that AVISE fills a critical diagnostic gap in lupus diagnosis," said Daniel Wallace, M.D., FACP, MACR, co-author of the evaluation, co-director of the Lupus and Sjogren's Clinic at Kao Autoimmunity Institute at Cedars-Sinai and board-certified rheumatologist at Beverly Hills Rheumatology in Los Angeles, Calif. "The AVISE Lupus algorithm demonstrated consistently robust diagnostic accuracy and outperformed the standard of care. For my patients, earlier and more definitive answers can make a real difference, and AVISE Lupus enhances my confidence in making that diagnosis."

Tyler O'Malley, Exagen Vice President of Clinical Affairs, Bioinformatics and Market Access, added, "This systematic evaluation provides meaningful real-world validation, expanding our evidence base with more comprehensive and current data. Building on the original AVISE Lupus clinical validation, the study demonstrated an AUC up to 0.90, specificity above 98% and unprecedented likelihood ratios. These results reinforce the durability and robustness of our proprietary algorithm, and strength of Exagen's intellectual property, and the high barriers to replicating our technology."

About Exagen

Exagen Inc. (NASDAQ:XGN) is a leading provider of autoimmune diagnostics, committed to transforming care for patients with chronic and debilitating autoimmune conditions. Based in San Diego County, California, Exagen's mission is to provide clarity in autoimmune disease decision-making and improve clinical outcomes through its innovative testing portfolio. The company's flagship product, AVISE® CTD, which incorporates the AVISE® Lupus algorithm, enables clinicians to more effectively diagnose complex autoimmune conditions such as lupus, rheumatoid arthritis, and Sjögren's disease earlier and with greater accuracy. Exagen's CLIA-certified, CAP-accredited laboratory specializes in the testing of rheumatic diseases, delivering precise and timely results, supported by a suite of AVISE-branded tests for disease diagnosis, prognosis, and monitoring. With a focus on research, innovation, education, and patient-centered care, Exagen is dedicated to addressing the ongoing challenges of autoimmune disease management.

For more information, visit Exagen.com or follow Exagen on LinkedIn.

Risk Factors

Exagen cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on Exagen's current beliefs and expectations. Such forward-looking statements include, but are not limited to, statements regarding: Exagen's goals, strategies and ambitions; the potential utility and effectiveness of Exagen's services and testing solutions and regarding Exagen's interpretation of clinical study results and management's views and evaluations of the same. The inclusion of forward-looking statements should not be regarded as a representation by Exagen that any of its plans will be achieved. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in Exagen's business, including, without limitation: delays in reimbursement and coverage decisions from Medicare and third-party payors and in interactions with regulatory authorities, and delays in ongoing and planned clinical trials involving its tests; Exagen's commercial success depends upon attaining and maintaining significant market acceptance of its testing products among rheumatologists, patients, third-party payors and others in the medical community; Exagen's ability to successfully execute on its business strategies; third-party payors not providing coverage and adequate reimbursement for Exagen's testing products, including Exagen's ability to collect on funds due; Exagen's ability to obtain and maintain intellectual property protection for its testing products; regulatory developments affecting Exagen's business; and other risks described in Exagen's prior press releases and Exagen's filings with the Securities and Exchange Commission (SEC), including under the heading "Risk Factors" in Exagen's Annual Report on Form 10-K for the year ended December 31, 2025, filed with the SEC on March 10, 2026 and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Exagen undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Investors:

Tina Jacobsen, CFA

Exagen Inc.

ir@exagen.com