CurrentPremera BluecrossPolicy N/A

Modifier 91 — Repeat Clinical Diagnostic Laboratory Test

Defines when Premera recognizes modifier 91 on professional claims to indicate clinical diagnostic laboratory tests repeated on the same date of service to obtain new test data; applies to Premera Blue Cross, Premera BCBS of Alaska, LifeWise Health Plan of Washington, LifeWise Assurance Company and Premera HMO lines of business and products.

Policy Summary

PayerPremera Bluecross

PolicyModifier 91 — Repeat Clinical Diagnostic Laboratory Test

Policy CodePolicy N/A

Change TypeAnnual reviewno material changes

Effective DateN/A

Next Review DateAug 4, 2025

Key ActionAppend modifier 91 when a clinical diagnostic laboratory test is performed multiple times on the same date of service to obtain new test data; do not use it solely to confirm initial results or for specimen/equipment issues.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

5Payer lines of business covered

annualReview frequency

Modifier 76Related modifier

CMS-1500Claim form applicability

When Modifier 91 Is Recognized

Coverage criteria for modifier 91

The Plan recognizes modifier 91 in specific circumstances and disallows it in others.

Modifier 91 is recognized when a clinical diagnostic laboratory test is performed multiple times on the same date of service to obtain new test data over the course of treatment.

Modifier 91 should not be appended when the repeat test is performed solely to confirm initial results.

Modifier 91 should not be appended when the repeat test is performed because of specimen or equipment testing problems during the initial test(s).

Do not use modifier 91 when another procedure code better describes the tests performed.

Do not append modifier 91 to a code whose description already indicates multiple tests are to be performed (for example, glucose).

Policy Summary

PayerPremera Bluecross

PolicyModifier 91 — Repeat Clinical Diagnostic Laboratory Test

Policy CodePolicy N/A

Change TypeAnnual reviewno material changes

Effective DateN/A

Next Review DateAug 4, 2025

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.

Billing Guidance for Providers

Billing Rule

Billing requirement — Use modifier 91 only for repeats to obtain new test data

Append modifier 91 to indicate a clinical diagnostic laboratory test was performed multiple times on the same date of service to obtain new test data; do not append modifier 91 when the repeat test is solely to confirm initial results, due to specimen/equipment testing problems, when another procedure code better describes the tests performed, or when the code description already indicates multiple tests (e.g., glucose).

Use modifier 91 only when tests are repeated to obtain new data over the course of treatment.
Do not use modifier 91 solely to confirm initial results or for specimen/equipment issues.
Do not use modifier 91 if another procedure code better describes the repeat test.
Do not append modifier 91 when the code description already specifies multiple tests (for example, glucose).

Key Definitions and Exceptions

Modifier 91 — definition and usage guidance

DefinitionIndicates a clinical diagnostic laboratory procedure or test was performed multiple times on the same day/date of service for the same patient to obtain new test data over the course of treatment.

Not for confirmation onlyDo not append modifier 91 when the repeat test is performed solely to confirm initial results.

Not for specimen/equipment issuesDo not append modifier 91 when the repeat test is due to specimen or equipment testing problems during the initial test(s).

Use alternative code when appropriateDo not use modifier 91 when another procedure code better describes the repeat tests or when the code description already specifies multiple tests (e.g., glucose).

Exceptions and related operational notes

Contract exceptionsExceptions to this policy may be made where a provider or employer group contract dictates otherwise.

EnforcementViolations may result in increased auditing/monitoring, contractual penalties, corrective action up to termination, at Plan discretion.

Scope applicabilityApplies to services submitted on professional claims for Premera Blue Cross, Premera BCBS of Alaska, LifeWise Health Plan of Washington, LifeWise Assurance Company and Premera HMO lines/products.

OpenPayer

Modifier 91 — Repeat Clinical Diagnostic Laboratory Test

When Modifier 91 Is Recognized

Modifiers and Code References

Billing Guidance for Providers

Key Definitions and Exceptions

Modifier 91	Repeat clinical diagnostic laboratory test performed multiple times on same date of service to obtain new test data
Modifier 76	Repeat procedure by the same provider (cross-referenced)