Plus Therapeutics Secures Medicare Enrollment for CNSide CSF Diagnostic Platform

Plus Therapeutics has cleared a foundational reimbursement hurdle for its CNSide® Cerebrospinal Fluid Assay Platform, with subsidiary CNSide Diagnostics, LLC receiving a Provider Transaction Access Number (PTAN) from the Centers for Medicare & Medicaid Services (CMS) — a prerequisite for submitting claims under Traditional Medicare Fee-For-Service. The milestone positions the laboratory to pursue formal coverage determinations and, eventually, pricing under the Clinical Laboratory Fee Schedule (CLFS).

Enrollment alone does not guarantee payment. Claims remain subject to coverage determinations by the local Medicare Administrative Contractor (MAC) with jurisdiction over the laboratory, meaning CNSide Diagnostics must now engage MACs to secure Local Coverage Determinations (LCDs) before reimbursement flows reliably. The company has indicated that CLFS pricing for CPT code 0640U — the CNSide CSF tumor cell enumeration (TCE) test — is targeted for establishment effective July 1, 2026, via crosswalk or gapfill methodology.

For laboratory directors and reimbursement leads tracking the commercialization arc, the PTAN also functions as credentialing infrastructure for state-by-state Medicaid enrollment, extending the platform's payer reach beyond the roughly 81 million commercial covered lives already under contract. The company has set a 2026 target of 150 million or more covered lives across commercial, Medicare, and Medicaid channels.

The CNSide CSF Assay Platform detects and characterizes tumor cells and circulating tumor DNA in cerebrospinal fluid, targeting leptomeningeal metastases — a CNS cancer complication where conventional imaging and cytology carry well-documented sensitivity limitations. The diagnostic's clinical utility argument, and by extension its LCD prospects, will depend on the real-world outcomes data the company is actively generating to support health economics submissions.

The next measurable checkpoint is MAC engagement and the CLFS pricing determination ahead of the July 2026 billing effective date.

Source: Plus Therapeutics, Inc. via GlobeNewswire, May 7, 2026.