Plus Therapeutics Subsidiary CNSide Diagnostics Secures National Coverage For CNSide® Test With UnitedHealthcare Agreement Covering 51 Million Patients

CNSide Diagnostics, LLC, a subsidiary of Plus Therapeutics, Inc. , has entered into a national agreement with UnitedHealthcare Insurance Company (NYSE: UNH), effective September 15, 2025. The deal provides coverage for more than 51 million Americans and grants access to the CNSide® Cerebrospinal Fluid Tumor Cell Enumeration test, a laboratory-developed test (LDT) designed to support patients with leptomeningeal metastases.

The CNSide® CSF Assay Platform delivers rapid and precise diagnostic insights, monitoring, and treatment guidance, outperforming current standard-of-care methods. Its clinical utility has been demonstrated in nine peer-reviewed publications and validated in the FORESEE clinical trial, as well as through widespread real-world adoption. Since 2020, over 11,000 tests have been performed across more than 120 U.S. cancer centers, with reported sensitivity of 92% and specificity of 95%, influencing treatment strategies in nearly 90% of cases.

Available exclusively through CNSide Diagnostics, the CNSide® test provides healthcare professionals with a powerful tool for detecting and characterizing tumor cells and circulating tumour DNA in the cerebrospinal fluid. By enabling molecular analysis of cancer spread to the central nervous system, CNSide® supports better patient management in those battling carcinomas and melanomas with leptomeningeal involvement.