Medicare AdvantageReimbursementHigh impact
[California] New combined reimbursement policy: Modifiers 90 and 91: Laboratory Services
Anthem BCBS·CA · Pathology·Claims & Billing
Effective date
Dec 1, 2026
We identified it
Sep 2, 2026
Summary
Anthem Blue Cross is implementing a new combined reimbursement policy for laboratory service modifiers 90 and 91, effective December 1, 2026. Modifier 90 (pass-through laboratory billing) is now NON-REIMBURSABLE for professional and outpatient facility providers—the performing provider must bill directly for 100% reimbursement. Modifier 91 (repeat clinical diagnostic lab tests) remains eligible for reimbursement at 100% on professional claims. The existing modifier 91 policy (G-06020) will be retired.
Action Required
By November 15, 2026: Billing team must update billing software and internal procedures to implement modifier 90 denial logic for Anthem Blue Cross Medicare Advantage claims in California. Specifically: (1) Configure system to automatically deny or reject any claims billed with modifier 90 by professional or outpatient facility providers; (2) Update provider communication templates to instruct providers that modifier 90 is not reimbursable and they must bill directly as the performing provider; (3) Retain existing modifier 91 reimbursement rules in billing system (no changes needed); (4) Train billing staff to identify and route modifier 90 claims for denial before submission; (5) Remove references to retired policy G-06020. Audit existing denied claims with modifier 90 to identify potential appeal opportunities for dates of service on or after December 1, 2026. Communicate policy change to in-network providers and facility partners in California. Failure to implement will result in claim denials and provider billing disputes.