CNSide Diagnostics, LLC, a subsidiary of Plus Therapeutics, Inc. (Nasdaq: PSTV), announced it has signed a national coverage agreement with Elevance Health, Inc. (NYSE: ELV), effective May 1, 2026, for its CNSide® Cerebrospinal Fluid (CSF) Tumor Cell Enumeration assay.

The agreement covers approximately 45.4 million people in the United States, bringing the CNSide assay's total contracted coverage to 126 million people nationwide, according to the company's press release.

The CNSide® CSF assay is designed to support diagnosis, treatment monitoring, and treatment guidance for patients with leptomeningeal metastases, a form of metastatic central nervous system cancer. The company states the assay has been performed more than 11,000 times at over 120 U.S. cancer institutions since 2020, with reported sensitivity of 92% and specificity of 95%. The company also claims it has influenced treatment decisions in 90% of cases.

The assay is available exclusively through CNSide Diagnostics as a laboratory testing service for health care professionals in the U.S. The company cited nine peer-reviewed publications and the FORESEE clinical trial as evidence of the assay's clinical utility.

Plus Therapeutics is headquartered in Houston, Texas, and is focused on developing targeted radiotherapeutics for central nervous system cancers.