CommercialCoverageHigh impact
Evaluation of Cerebrospinal fluid, Urine, and Plasma Tests for Alzheimer Disease (2.04.14)
Blue Shield of California·CA · Neurology, Geriatrics, Internal Medicine +1 more·Medical Policy
Effective date
Aug 1, 2026
We identified it
Jul 31, 2026
Summary
Blue Shield of California significantly narrowed coverage for Alzheimer's biomarker testing effective August 1, 2026. CSF testing for amyloid beta and tau is now covered ONLY when using three specific FDA-approved tests as part of evaluation for initiating amyloid beta-targeting therapy (lecanemab/donanemab) in patients with mild cognitive impairment or mild dementia. Plasma testing and all other scenarios (diagnostic adjunct, continuation therapy, neural thread proteins, urine testing) are classified as investigational and not covered.
Action Required
By July 15, 2026: Billing team must implement the following changes: (1) Require prior authorization and medical necessity documentation for CPT/PLA codes 0459U (Elecsys ß-Amyloid/Total-Tau CSF) and 0445U (Elecsys Phospho-Tau 181P Plasma) ONLY when ordered for initiation of amyloid beta-targeting therapy in patients with MCI or mild dementia AND using one of three approved test kits (Lumipulse G Aβ42:Aβ40 ratio, Elecsys Aβ42:p-tau181, or Elecsys Aβ42:total-tau); (2) Update billing system rules to DENY all other biomarker testing scenarios (diagnostic adjunct use, continuation therapy monitoring, neural thread proteins, urine analytes, plasma testing outside the three approved configurations); (3) Update provider order entry forms and prior auth templates to restrict coverage criteria; (4) Train billing staff on coverage limitations. Providers must document the specific FDA-approved test kit being used and confirm patient meets criteria (MCI or mild AD dementia with therapy initiation planned). Failure to comply will result in claim denials for non-covered testing scenarios and delays in authorization for covered tests.