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    v1.0.30
    OpenPayerPolicy UpdatesReimbursement/Payment PolicyWellpoint Modifiers 90/91 Coverage Update | OpenPa…
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    CurrentWellpointPolicy G-20001

    Reimbursement Policy Modifiers 90 and 91: Laboratory Services

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    This policy governs reimbursement and claim submission for modifiers 90 and 91 on professional and outpatient facility claims under Wellpoint Iowa Health Link and Hawki.

    Policy Summary
    PayerWellpoint
    PolicyReimbursement Policy Modifiers 90 and 91: Laboratory Services
    Policy CodePolicy G-20001
    Change TypePolicy consolidation
    Effective DateJan 1, 202755d
    Last ReviewJul 22, 2026
    Next Review DateN/A
    Key ActionUse modifier 91 only for medically necessary repeat clinical diagnostic testing performed more than once on the same day for the same patient.
    SourceLink
    POLICY UPDATE CHANGES

    Modifier 90 and Modifier 91 requirements are now combined in one policy.

    The policy title was revised.

    90 and 91Laboratory modifiers addressed
    100%Eligible service reimbursement rate
    0Modifier 90 reimbursement eligibility
    1 unitMultiple-unit reimbursement limit

    OpenPayer is powered by Trek Health's payer performance platform. Trek continuously ingests, validates, and normalizes Transparency in Coverage data alongside payer policies and other commercial payer data to create a structured payer intelligence foundation. OpenPayer uses this foundation to deliver personalized search results, dynamically generated policy pages, and tailored policy monitoring based on each user's payers, specialties, billing codes, and areas of interest. The same intelligence powers broader payer performance workflows, including reimbursement benchmarking, contract evaluation, payer negotiations, and financial decision-making.

    Laboratory Modifier Coverage Criteria

    Modifier 90: Reference laboratory services

    Modifier 90 laboratory services are not eligible for reimbursement when used for pass-through billing.

    ALL of the following

    • A laboratory service is billed with modifier 90 on a professional or outpatient facility claim

      The claim is not eligible for reimbursement because pass-through billing is not allowed.

    ALL of the following

    • The service is a pathology service reported with modifier 90 by a pathology provider

      The stated modifier 90 prohibition does not apply to these pathology services.

    ALL of the following

    • The provider or outpatient facility performed the laboratory test

      Reimbursement is made directly to the performing provider at 100% of the applicable fee schedule or contracted/negotiated rate.

    Modifier 91: Repeat clinical diagnostic laboratory tests

    Modifier 91 repeat clinical diagnostic laboratory tests may be reimbursed when used appropriately.

    ALL of the following

    • The same clinical diagnostic laboratory test is performed more than once on the same day for the same patient to obtain subsequent results during treatment

      The repeat test may be separately reimbursed at 100% of the applicable fee schedule or contracted/negotiated rate.

    Any of the following applies

    • Only one test result is required
    • The test is rerun to confirm an initial result
    • Testing problems with specimens or equipment caused the rerun

    Modifier Coding and Reimbursement Rules

    Modifier 90ModifierNot Covered
    90Reference (outside) laboratory modifier
    Modifier 91ModifierCovered
    91Repeat clinical diagnostic laboratory test modifier
    Eligible Reimbursement Rate
    Eligible reimbursement rate100% of the applicable fee schedule or contracted/negotiated rate
    Modifier 90 laboratory servicesReimbursement is made directly to the provider that performed the clinical diagnostic laboratory test
    Modifier 91 repeat testsRepeat clinical diagnostic laboratory tests appended with modifier 91 are eligible for reimbursement at the applicable rate
    Repeat Testing Frequency
    FrequencyMore than once on the same day
    PatientThe repeat test must be performed on the same patient

    Billing and Documentation Actions

    Billing Rule

    Apply laboratory modifiers according to policy

    Append modifier 90 or 91 only in accordance with this policy and applicable provider, state, federal, CMS, or contractual requirements.

    Billing Rule

    Bill performed laboratory services without pass-through billing

    Do not use modifier 90 for pass-through billing of laboratory services. The provider or outpatient facility that performed the test must submit the claim; pathology providers may report pathology services with modifier 90.

    Billing Rule

    Use modifier 91 only for medically necessary same-day repeat testing

    Billing Terminology

    Pass-Through Billing
    Who pays the laboratoryA provider, such as a physician or hospital, pays a laboratory to perform the tests
    Who performs the testsThe laboratory performs the provider's tests
    How claims are filedThe provider files the claims as though the provider had performed the tests themselves
    Policy Summary
    PayerWellpoint
    PolicyReimbursement Policy Modifiers 90 and 91: Laboratory Services
    Policy CodePolicy G-20001
    Change TypePolicy consolidation
    Effective DateJan 1, 202755d
    Last ReviewJul 22, 2026
    Next Review DateN/A
    Key ActionUse modifier 91 only for medically necessary repeat clinical diagnostic testing performed more than once on the same day for the same patient.
    SourceLink
    On This Page
    Laboratory Modifier Coverage CriteriaModifier Coding and Reimbursement RulesBilling and Documentation ActionsBilling Terminology
    Another code describes a series of test results

    ALL of the following

    • Medical documentation supports appropriate use of modifier 91

      Documentation may be requested.

    ALL of the following

    • The procedure is billed with multiple units and only one unit is permitted

      Reimbursement is based on a single unit.

    ALL of the following

    • Modifier 91 is used inappropriately

      The repeated laboratory test may be denied as a duplicate service.

    PurposeThe repeat test is performed in the course of treatment to obtain subsequent multiple test results
    Multiple-Unit Reimbursement Limit
    Multiple-unit billingThe procedure is billed with multiple units
    Permitted unitsOnly one unit is permitted
    Reimbursement limitReimbursement will be based on a single unit

    Use modifier 91 only when the same clinical diagnostic laboratory test is performed more than once on the same day for the same patient to obtain subsequent results that are medically needed. Do not use it for a single required result, confirmation of an initial result, testing problems, series-testing codes, or other inappropriate circumstances.

    Documentation Required

    Support repeat testing with medical documentation

    Maintain medical documentation supporting the appropriate use of modifier 91, because documentation may be requested.

    Denial Risk

    Avoid duplicate-service denials

    Use modifier 91 appropriately to avoid denial of the repeated laboratory test as a duplicate service.