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[California] New combined reimbursement policy: Modifiers 90 and 91: Laboratory Services
Act
by Nov 15, 2026
Effective date
Dec 1, 2026
Identified
Sep 2, 2026
Summary
Anthem Blue Cross Medi-Cal is implementing a new combined reimbursement policy for laboratory modifiers 90 and 91 effective December 1, 2026. Modifier 90 (pass-through lab billing) will no longer be reimbursed except in specific circumstances (outside lab services billed by another provider using HCPCS S3620 or CPT 81528, or pathology services). Modifier 91 (repeat lab tests) remains eligible for reimbursement at 100% of fee schedule. The existing modifier 91 policy (G-06020) will be retired and consolidated into the new policy (G-20001).
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What to do
by Nov 15, 2026 · 8 steps
01Billing team must update billing system rules and provider documentation to implement new modifier 90/91 policy.
02Configure system to deny reimbursement for modifier 90 claims EXCEPT when billed by outside laboratory providers using HCPCS S3620 or CPT 81528, or by pathology providers.
03Remove modifier 90 from standard laboratory service workflows unless outside lab exception applies.
04Verify modifier 91 claims continue to process at 100% reimbursement without interruption.
05Update all internal billing guidelines, encounter forms, and provider training materials to reflect policy change.
06Notify all affected providers and outpatient facilities of the new requirements.
07Do NOT balance bill members based on this policy change.
08Claims not complying with the new modifier 90 restrictions will be denied effective December 1, 2026.
Codes mentioned
S362081528
Original notice
[California] New combined reimbursement policy: Modifiers 90 and 91: Laboratory Services
providernews.anthem.com · Always check the source before changing claims.
Related changes
See all Anthem BCBS changes →[California] New combined reimbursement policy: Modifiers 90 and 91: Laboratory ServicesHighEffective Dec 1, 2026 · Claims & Billing[New York] New combined reimbursement policy: Modifiers 90 and 91: Laboratory ServicesHighEffective Dec 1, 2026 · Claims & Billing[New York] New combined reimbursement policy: Modifiers 90 and 91: Laboratory ServicesHighEffective Dec 1, 2026 · Claims & Billing[Ohio] New combined reimbursement policy: Modifiers 90 and 91: Laboratory ServicesHighEffective Dec 1, 2026 · Claims & BillingBrowse every Anthem BCBS change in the policy list