CPT® Code 87428

Last Updated: February 2026 | Verified for 2026 AMA, CPT & CMS Billing Frameworks (Medicare LCD/Article + CLIA Waiver Rules)

Quick Reference:

• What CPT 87428 means: A single, combined antigen immunoassay (e.g., EIA/FIA) performed on a respiratory specimen for simultaneous qualitative detection of SARS-CoV-2 and influenza A and B. It is an antigen test (not NAAT/PCR).
• Medicare coverage anchor: Medicare commonly treats 87428 within Respiratory Pathogen Panel Testing policy logic. Coverage is tied to outpatient clinical utility, timely reporting, and documentation that the result will meaningfully inform management consistent with LCD and its companion billing/coding article.
• Panel integrity ("do not unbundle"): When 87428 is used, it represents one unit of service for the combined panel. Billing influenza components separately (or stacking overlapping respiratory panel codes for the same specimen/encounter) is a frequent denial trigger under Medicare policy logic described in the coverage article.
• Modifier QW is typically required: Because 87428 is a CLIA-waived test when performed under a Certificate of Waiver, Medicare requires reporting as 87428-QW when appropriate. CMS issued explicit instruction adding QW to 87428 effective for waived testing.
• Commercial payer behavior is similar (but not identical): Many commercial plans apply "limited panel" logic (often 5 targets or fewer) and require that testing is ordered for patients meeting clinical criteria and where results will change management. Anthem's outpatient respiratory viral panel policy is a representative example of this approach.
• Documentation is the denial line: The medical record must support (1) why testing was needed now (symptoms, exposure, risk, or clinical decision point), (2) specimen type and method, (3) ordering/referring information and signatures per payer expectations, and (4) that the service billed matches what was performed per Medicare billing/coding requirements.

CPT 87428 is widely used in outpatient clinics, urgent care, and office settings for rapid differentiation of influenza A/B versus COVID-19 when symptoms overlap.

Most payment risk does not come from the science of antigen detection; it comes from policy friction:

1. using the code in low-utility situations that payers view as routine screening,
2. insufficient documentation tying the test to a clear management decision,
3. missing or incorrect CLIA-waived (QW) reporting where required, and
4. duplicate or overlapping respiratory testing billed for the same encounter/specimen.

This 2026-focused guide converts Medicare's LCD/Article logic and common commercial policy themes into a payer-realistic, audit-defensible approach to ordering, documenting, and billing 87428.

1. Definition and Procedure Scope

CPT 87428 describes a combined antigen immunoassay performed on a respiratory specimen for detection of SARS-CoV-2 and influenza A and influenza B. The defining features are (a) antigen detection (immunoassay), (b) combined reporting in one code, and (c) typical use in point-of-care or near-patient workflows where rapid clinical decisions are made. AAPC's Codify description summarizes the service as an immunoassay for qualitative/semiquantitative evaluation of patient specimens for antigens of SARS-CoV-2 and influenza A/B.

1.1 What 87428 is (and is not)

• It is an antigen test: It identifies viral antigens via immunoassay methodology. It is not a nucleic-acid amplification test (NAAT) or PCR.
• It is a single combined panel code: It represents one test service that yields separate qualitative results for influenza A, influenza B, and SARS-CoV-2.
• It is commonly CLIA-waived when performed with waived methods: Many outpatient implementations are under a CLIA Certificate of Waiver, which drives QW modifier reporting rules for Medicare.

1.2 Specimen and operational context

87428 is typically performed on respiratory specimens commonly used for outpatient viral testing (for example, nasal or nasopharyngeal swabs), depending on the manufacturer's instructions and the site's testing protocol. For billing defensibility, the record should identify:

• Specimen type (e.g., nasal swab) and collection date/time when relevant
• Where the test was performed (office, urgent care, outpatient clinic, etc.)
• The test platform or kit used when your payer or internal compliance program requires traceability (best practice)

Practical boundary: Do not use CPT 87428 to represent a molecular (PCR/NAAT) respiratory panel. Payers treat antigen and molecular methodologies differently, and billing the wrong methodology code is an avoidable denial and recoupment risk. Use the code that matches what was actually performed and documented.

2. Medicare Coverage Framework (LCD + Article)

For Medicare, the most defensible way to approach 87428 is to treat it as governed by the Respiratory Pathogen Panel Testing coverage framework in the relevant LCD and its companion Billing & Coding Article. The LCD describes when outpatient respiratory pathogen panel testing is reasonable and necessary, emphasizing the importance of timely results and actionable clinical impact.

2.1 The core Medicare "reasonableness" logic

The LCD's outpatient framework is centered on a straightforward payer question: Will the result be available quickly enough to change care, and will it plausibly improve outcomes? The LCD states that outpatient settings must be equipped to deliver timely results to providers, and the test must aid clinical management with improved health outcome.

In practice, Medicare medical necessity for 87428 is most defensible when documentation shows the test is ordered at a decision point such as:

• Choosing antiviral therapy, isolation precautions, or return-to-work/school guidance when clinically appropriate
• Determining whether symptoms are more consistent with influenza vs COVID-19 when that distinction affects management
• Supporting disposition decisions (home care vs escalation) in higher-risk patients when the result will influence follow-up intensity or treatment choices

2.2 The Billing & Coding Article matters operationally

Medicare denials often occur not because the clinical scenario is unreasonable, but because the claim and the record do not satisfy the billing/coding article's documentation expectations. The Article on Respiratory Pathogen Panel Testing addresses:

• Documentation expectations and record support for the ICD-10 code selection
• Coverage-linked diagnosis coding and claim alignment expectations
• Policy cautions against inappropriate billing patterns (including "panel integrity" behaviors)

This is where many practices lose appeals: they describe symptoms in a note, but do not clearly connect the test to medical necessity and management impact, or they select diagnoses that do not align with payer coverage logic.

Medicare compliance focus: When a claim is reviewed, Medicare contractors often treat the order, the clinical note, and the testing record as one "medical necessity packet." If the packet does not clearly show why the test was necessary and how it informed care, the claim is vulnerable even if the patient truly had an infection.

3. Commercial Payer Coverage Themes (Outpatient)

Commercial insurers often mirror Medicare's general logic but apply it through plan medical policies that emphasize limited panels, high-risk indications, and impact on management. A representative example is Anthem's outpatient respiratory viral panel policy, which supports testing when panels are limited (often 5 targets or fewer), patients meet clinical criteria, and results are expected to guide or alter management.

3.1 What commercial payers commonly restrict

Even though 87428 is a 3-target panel (and therefore generally fits "limited panel" definitions), commercial payers may deny if documentation suggests:

• Routine screening in low-risk patients without an actionable decision point
• Testing performed when the result will not change management (e.g., already confirmed diagnosis with no change in plan)
• Repeat testing without a documented new clinical reason (new symptoms, new exposure, or a management change)

3.2 Frequency limits are plan-specific

Commercial policies frequently include utilization controls such as:

• Limits per illness episode
• Limits per season (especially for influenza)
• Prior authorization triggers for repeated respiratory testing

Because these limits vary significantly by product and employer group, the most reliable rule is operational: document the new clinical question each time a repeat test is ordered, and ensure your billing team can defend medical necessity and distinctness of the episode.

Commercial reality: Even when a test is clinically reasonable, payers may expect that multiplex testing is reserved for cases where the differential diagnosis will meaningfully alter care. If the chart reads like "test performed because patient requested it" without clinical decision context, denials are common.

4. ICD-10 Coding and Medical Necessity

Correct ICD-10 selection is not a cosmetic step; for many respiratory testing policies it is the primary medical necessity signal that claims systems and contractors use. Medicare's companion billing/coding article provides diagnosis coding and related documentation expectations for respiratory pathogen panel testing.

4.1 Diagnosis coding principles that reduce denials

• Use diagnoses that match the clinical story: acute respiratory symptoms, suspected influenza/COVID-19, or clinically relevant exposure contexts.
• Avoid mismatch diagnoses: "routine exam" or unrelated chronic diagnoses on the test line invite claim edits and denials.
• Link diagnoses correctly: the test line should be linked to the respiratory complaint/suspected infection or exposure rationale documented for the encounter.

4.2 Common ICD-10 patterns (practical, payer-aligned)

The following categories are commonly used in real-world claims for 87428 when supported by documentation and consistent with Medicare respiratory testing policy logic:

• Influenza diagnoses (J09-J11 series): used when influenza is suspected or confirmed and testing supports diagnosis and management.
• COVID-19 diagnosis (U07.1): used when COVID-19 is confirmed (or when payer rules permit suspected use consistent with documentation).
• Exposure to COVID-19 (Z20.822): used when the clinical record supports a relevant exposure-based rationale for testing.

Documentation-driven coding: Do not "upgrade" diagnosis codes to improve payment. Payers and auditors expect the diagnosis on the claim to be supported by the provider's assessment and the clinical record. Medicare policy explicitly ties documentation to ICD-10 support expectations in the Respiratory Pathogen Panel testing framework.

5. Modifier QW and CLIA Waiver Requirements

5.1 When QW applies

Modifier QW signals that the test is performed as a CLIA-waived test. When 87428 is performed in a waived setting under the appropriate CLIA Certificate of Waiver, Medicare requires reporting as 87428-QW. CMS explicitly addressed the addition of modifier QW to 87428 in MLN Matters guidance.

5.2 What to operationalize for clean claims

To reduce denials related to CLIA/QW mechanics:

• Ensure CLIA information is correct in the billing system for the performing entity/location.
• Append QW consistently when the test is performed as waived and the payer requires it (Medicare and many commercial payers).
• Align performing location with the claim (place of service) so that the site that performed the test is consistent with the CLIA certification context.

High-yield risk: Medicare denials commonly occur when QW is omitted for waived testing or when the claim suggests a waived test was performed by an entity/location that does not appear appropriately certified in payer systems. CMS instruction on QW for 87428 is the baseline reference for Medicare claims behavior.

6. Bundling, Panel Integrity, and Duplicate Testing

While drug administration codes have explicit NCCI edits, respiratory pathogen panels create similar problems through policy logic and claims editing: payers expect that a defined panel code is not split into components and is not stacked with overlapping tests on the same specimen/encounter without clear justification.

Medicare's Respiratory Pathogen Panel Testing billing/coding article is the key anchor for understanding how Medicare operationalizes these expectations.

6.1 Panel integrity: one panel equals one service

When 87428 is billed, it represents the combined service for the three targets. Billing separate influenza antigen codes for influenza A and influenza B on the same specimen/encounter is typically inconsistent with the purpose of a combined panel code and is a common denial pattern in practice when claims are reviewed under respiratory panel policy logic.

6.2 Avoiding duplicate testing patterns

The highest-risk duplicate patterns in outpatient settings include:

• Antigen + antigen duplication: billing 87428 and a separate SARS-CoV-2 antigen test code for the same encounter/specimen without documented medical necessity for repeat/confirmatory testing.
• Antigen + NAAT stacking: billing an antigen panel and a molecular panel for the same targets during the same encounter without documentation supporting why both were needed (e.g., discordant result resolution or a change in management plan).

Denial trigger: If the chart does not clearly justify why two tests for the same targets were needed (and why one test was insufficient), payers may deny one as duplicative. Medicare's billing/coding framework for respiratory panels is the most defensible baseline for avoiding these patterns.

7. Documentation Standards (Audit-Proofing)

Denials for 87428 are frequently documentation-driven rather than technology-driven. Medicare's LCD and billing/coding article emphasize that medical records must support the claim and the ICD-10 selection, including the rationale for testing and the expectation of clinical utility.

7.1 Minimum documentation elements (best practice)

For an audit-resistant record, ensure the chart supports:

• Clinical indication: symptoms (e.g., fever, cough, myalgias), exposure, risk status, or a clinical decision point.
• Why the result matters: how it will change care (antivirals, isolation guidance, escalation, follow-up intensity, return-to-work rules when clinically appropriate).
• Ordering provider information: order or attestation consistent with your setting's policy.
• Specimen and method: specimen type, collection context, and that an antigen immunoassay panel was performed.
• Result reporting: separate results for SARS-CoV-2, influenza A, influenza B, and the time the result was available (especially important in urgent care workflows).

7.2 Documentation patterns that strengthen appeals

Claims are more defensible when the record includes one or more of the following:

• Risk-based rationale: age, comorbidities, immunocompromise, pregnancy, or other risk factors that justify a rapid confirmatory diagnosis affecting management.
• Therapeutic consequence: explicit mention that antiviral therapy is being considered or that alternative management pathways depend on the result.
• Disposition consequence: the result will influence whether the patient can be safely managed outpatient or requires closer monitoring.

Common documentation failure: "Test ordered" without explaining what decision hinges on the result often reads to payers like low-utility testing. Medicare's LCD/Article framework emphasizes clinical utility and documentation support; build those concepts into your note templates.

8. Real-World Billing Scenarios

Scenario 1: Office visit with point-of-care antigen panel

Setting: Physician office (typical POS 11). Clinical story: Patient presents with acute fever, cough, body aches during influenza/COVID circulation; clinician needs rapid differentiation to guide management and counseling. Service: Antigen immunoassay panel performed on a respiratory specimen; results available during visit. Billing logic: Bill 87428-QW (when performed as waived); link to an appropriate respiratory diagnosis consistent with the note. Documentation tip: Explicitly state why the result affects management and that the test was a combined antigen panel. Medicare QW instruction is the baseline for waived reporting.

Scenario 2: Urgent care with same-day management decisions

Setting: Urgent care / outpatient clinic. Clinical story: Higher-risk patient with acute respiratory symptoms; clinician is considering antiviral therapy and needs immediate result. Service: Combined antigen panel performed; result reported quickly. Coverage logic: This scenario aligns with the outpatient utility logic emphasized in Medicare's respiratory pathogen panel LCD: timely reporting and management impact. Denial prevention: Include risk factors and the management decision point in the note to defend medical necessity.

Scenario 3: Repeat testing request without a new clinical rationale

Setting: Office follow-up 2 days after a negative panel. Clinical story: Patient requests retesting "to be sure," but symptoms are improving and no new exposure or management decision is documented. Risk: Many payers treat this as low-utility repeat testing and may deny as not medically necessary or duplicative under respiratory testing policy logic. Best practice: If retesting is clinically necessary, document the specific new clinical reason (new symptoms, clinical deterioration, new exposure, or a management change) consistent with Medicare documentation expectations in the respiratory panel policy framework.

Scenario 4: Antigen panel followed by molecular testing

Setting: Outpatient setting where confirmatory NAAT is available. Clinical story: Antigen panel result is inconsistent with clinical presentation (e.g., high suspicion with negative result) and confirmatory testing is ordered for a documented reason. Billing caution: Without documentation explaining why both methods were required, payers may deny one as duplicative. The Medicare respiratory panel billing/coding framework is the safest baseline for explaining and defending why additional testing was required.

9. Comparison Table: 87428 vs Common Alternatives

Key point: Payers generally expect you to choose the one test method that answers the clinical question. If multiple tests are used, the chart must make it obvious why the additional test was medically necessary and not duplicative. Medicare's respiratory panel policy logic is the most defensible baseline for structuring that documentation.