Lupus Tests

Exagen Launch of Novel Biomarker PC4d Associated with Thrombosis in Lupus

Makers of the rapidly growing AVISE CTD test expands portfolio of patented CB-CAPs blood tests.

ALBUQUERQUE, NM and SAN DIEGO, CA, Oct 12, 2018 (GLOBE NEWSWIRE) – Exagen Diagnostics, a leader in autoimmune life sciences, announced today that it will be updating the popular AVISE® SLE Monitor test to include levels of platelet-bound C4d (PC4d). Exagen will be the only laboratory offering this unique biomarker which is significantly associated with thrombosis in patients with systemic lupus erythematosus (SLE).

The announcement comes the day before World Thrombosis Day (WTD), an event taking place on October 13 that aims to increase awareness about this deadly condition responsible for 1 in every 4 deaths worldwide. Patients with SLE are especially prone to thrombosis but distinguishing which SLE patients have an increased association with thrombotic events is a challenge that healthcare providers are eager to overcome. In a scientific presentation scheduled for Oct 23 in Chicago, researchers will be reporting that SLE patients with thrombosis presented with a 5.5 fold higher median PC4d level compared to SLE patients without a history of thrombosis. Other studies have shown that persistent positive PC4d levels in SLE patients are significantly associated with ischemic stroke.

More women aged 15-24 die every year from SLE that any other chronic inflammatory disease and African American and Hispanic women are disproportionately affected by the disease.3 There is no known cause nor cure for SLE so managing symptoms and tryingto avoid life threatening organ involvement is the focus of any treatment regimen. According to Exagen CEO Ron Rocca, “Our company is focused on improving the diagnosis, prognosis, and monitoring of conditions like SLE in order to improve the lives of patients.”

According to Dr. James Mossell, Rheumatologist in Tifton, GA. “In the management of lupus, there are many variables and the biggest unknown is insight into when disease activity is increasing and a flare or thrombotic event may strike. I have found the AVISE SLE Monitor test very useful in my practice and am hopeful that the addition of PC4d will provide additional insight that leads to improved outcomes for my SLE patients.”

The new PC4d test, scheduled to be available before the end of October, measures Cell-bound Complement Activation Product or “CB-CAPs” using flow cytometry. The Lupus Foundation of America contributed to initial research that led to the development of the AVISE Lupus Test which was the first test available using CB-CAPs. Now exclusively commercialized by Exagen Diagnostics, the company continues to invest in critical research to help providers tailor their care in hopes of improving the lives of patients with autoimmune diseases like SLE.

1. Petri M, et al. Complement C4d Split Products in Combination with Lupus Anticoagulant and Low Complement Associate with Thrombosis in SLE [abstract]. Arthritis Rheumatol. 2018; 70.
2. Kao A, et al. Relation of platelet C4d with all-cause mortality and ischemic stroke in patients with systemic lupus erythematosus. Transl Stroke Res 2014; 5(4):510-518.
3. Yen E. et al. Lupus – An Unrecognized Leading Cause of Death in Young Women: Population-based Study Using Nationwide Death Certificates, 2000-2015. Arthritis Rheumatol. 2018 Apr 18. doi: 10.1002/art.40512

To learn more about Exagen Diagnostics, please visit

About Exagen’s AVISE laboratory tests

AVISE Connective Tissue Disease (CTD) is a diagnostic test which supports care providers with an accurate assessment of critical biomarkers in patients suspected of SLE or rheumatic conditions with similar symptoms. AVISE Lupus uniquely incorporates biologically-relevant CB-CAPs (Cell-Bound Complement Activation Products) into a proprietary algorithm that yields an index value which is associated with the likelihood for the presence of SLE. This amounts to a convenient test for the differential diagnosis of SLE with demonstrated performance of 80% sensitivity and 86% specificity. CB-CAPs provide 22% higher sensitivity for SLE than standard complement measures C3 or C4 alone. The AVISE Lupus test offers 48% greater sensitivity than traditional anti-dsDNA alone.

AVISE SLE Monitor is a combination of five advanced tests and provides important data to assist physicians anytime they assess the status of a patient with SLE. This test employs erythrocyte bound C4d (EC4d) along with other key markers which have demonstrated significant correlation to SLE disease activity. AVISE SLE Monitor gives the treating care provider an accurate glimpse into the serologic measures of disease activity allowing for a more complete picture of how well a patient’s condition is being managed.

About Exagen

Exagen is a commercial stage life sciences company that is patient focused, and discovery driven. Exagen serves patients and healthcare providers across the U.S. in the diagnosis, prognosis, and management of lupus, rheumatoid arthritis, and other autoimmune conditions. By leveraging our patented and validated Cell-bound Complement Activation Products (CB-CAPs) technology we can help get to the real cause of a patient’s symptoms and guide their journey to improved health. For more information, visit or follow us on Facebook, Twitter, YouTube, LinkedIn, or Instagram.

Exagen, AVISE, and the Exagen and AVISE logos are registered trademarks of Exagen Diagnostics Inc.

Key Words: Lupus, Lupus Diagnosis, #LupusLabFacts, Autoimmune, Laboratory, AVISE CTD, AVISE, #WTDay18, #KnowThrombosis, #KeepLifeFlowing, #WorldThrombosisDay

Contact: Brian McEvilly
Exagen Diagnostics, Inc.