Alzheimer's Disease Tests

Aetna covers CSF lumbar puncture testing for elevated P‑tau/T‑tau and reduced Aβ42 or low Aβ42/Aβ40 ratio to assess MCI when AD is suspected, brain MRI for aducanumab/lecanemab patients (within 1 year pre‑treatment and at specified dosing intervals to evaluate ARIA), and APP/PSEN1/PSEN2 genetic testing for patients <50 being considered for aducanumab/lecanemab clinical trial enrollment (amyloid PET is handled under a separate policy). These services are payable only if the policy’s specific medical‑necessity/selection criteria and timing/age/trial‑enrollment requirements are met, while a broad list of other biomarkers/tests and many listed CPT/HCPCS/ICD‑10–specified services are considered experimental/investigational and not covered.

"Plasma p-tau231 findings, while promising, require validation in longitudinal and larger cohorts and are not yet definitive for routine clinical use."