CurrentAnthemPolicy G-07022

Modifiers LT and RT: Left-Side and Right-Side Procedures

Defines Anthem Blue Cross (Medi‑Cal Managed Care California) reimbursement stance and billing guidance for use of modifiers LT and RT when indicating the side of the body for procedures, and describes effects on reimbursement and bilateral billing rules.

Policy Summary

PayerAnthem

PolicyModifiers LT and RT: Left-Side and Right-Side Procedures

Policy CodePolicy G-07022

Change TypeNo material change

Effective DateJul 21, 2025

Next Review Date

Key ActionEnsure appropriate authorization and medical necessity are met and include supporting documentation when submitting claims with LT/RT modifiers.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

100%reimbursement basis

0payment impact

1policy updates

2related policies

Coverage Criteria for LT/RT Modifiers

LT/RT modifier coverage criteria

Conditions under which LT/RT modifiers are acceptable and how they affect reimbursement:

ALL of the following

LT and RT modifiers are allowed to indicate the side of body for which the procedure/item/supply is used.
Reimbursement is based on 100% of the fee schedule or contracted/negotiated rate; LT/RT are informational and do not change payment amount.
Do not append LT or RT when billing for bilateral procedures or with procedure codes whose description contains 'bilateral' or 'unilateral'.
If claims are submitted with LT and RT indicating procedures were performed on both sides, they are subject to multiple surgery rules.

Policy Summary

PayerAnthem

PolicyModifiers LT and RT: Left-Side and Right-Side Procedures

Policy CodePolicy G-07022

Change TypeNo material change

Effective DateJul 21, 2025

Next Review Date

Key ActionEnsure appropriate authorization and medical necessity are met and include supporting documentation when submitting claims with LT/RT modifiers.

SourceLink

On This Page

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Coding: Side-specific Modifiers and Appropriate Use

Side-specific modifiersModifier

LT	Modifier indicating left side
RT	Modifier indicating right side

Inappropriate use — LT/RT modifiers

RuleDo not append modifier LT or RT when billing for bilateral procedures or when the procedure code descriptor already contains 'bilateral', 'unilateral', or 'both'.

RationaleModifiers LT and RT are informational and do not indicate bilateral services; inappropriate use may result in application of multiple surgery rules or contract requirements.

Reimbursement impactLT/RT do not increase or decrease reimbursement; payment remains 100% of the fee schedule or contracted/negotiated rate.

Provider Billing and Submission Actions

Prior Authorization

Authorization, Documentation, and Claim Submission

Ensure appropriate authorization and medical necessity guidelines are met and use proper billing and submission guidelines. Services must be billed with industry-standard, compliant codes (CPT, HCPCS, revenue codes) and fully supported in the medical record. If coding/billing guidelines or reimbursement policies are not followed, claims may be rejected, denied, or subject to recovery/recoupment.

Use CPT, HCPCS, and/or revenue codes that accurately describe the service.
Support billed services in the medical record and office notes.
Follow any applicable provider, state, federal, or CMS contract requirements.

Denial Risk

Multiple Surgery Rule Risk

Claims that include modifiers LT and RT to indicate left and right sides are informational and do not by themselves indicate bilateral procedures; when such modifiers are used to reflect that a surgical procedure was performed on both sides, those claims are subject to multiple surgery rules and any applicable contract requirements. It is inappropriate to use LT/RT with procedure codes that already describe bilateral services.

Modifiers LT and RT are informational and do not change reimbursement (reimbursement based on 100% of fee schedule or contracted rate).
Do not append LT/RT to procedure codes that are described as bilateral or unilateral/bilateral.
When LT and RT indicate procedures were performed on both sides, expect application of multiple surgery rules and potential payment adjustments.
Ensure documentation clearly supports side-specific services and any bilateral procedure reporting.

Definitions

Bilateral

DefinitionProcedures performed on both sides of the body during the same operative session.

Billing noteUse of LT/RT does not indicate a bilateral procedure; bilateral procedures should be billed per applicable bilateral or multiple-surgery guidance.

Reimbursement considerationClaims indicating bilateral procedures are subject to multiple surgery rules and standard contract requirements.

Modifier LT

DefinitionLeft side (used to identify procedures performed on the left side of the body).

UsageAppend modifier LT to procedure codes to indicate the left side when appropriate and when code descriptor does not already specify laterality.

Payment impactModifier LT is informational and does not change reimbursement; payment is based on fee schedule/contracted rate.

Modifier RT

DefinitionRight side (used to identify procedures performed on the right side of the body).

UsageAppend modifier RT to procedure codes to indicate the right side when appropriate and when code descriptor does not already specify laterality.

Payment impactModifier RT is informational and does not change reimbursement; payment is based on fee schedule/contracted rate.

Unilateral

DefinitionProcedures performed on one side of the body.

DistinctionUnilateral indicates a single-side procedure; do not append LT/RT when the code descriptor already states 'unilateral'.

Billing guidanceWhen a procedure is unilateral, append the appropriate side modifier (LT or RT) only if the code descriptor does not already convey laterality.