Exagen Announces Launch of Novel Biomarker PC4D Asociated 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 one in every four 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.2

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 trying to 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 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 www.Exagen.com