CPT® Code 87400 is used to report infectious agent antigen detection for influenza A or B using an enzyme immunoassay (EIA) method. This test identifies the presence of influenza viral antigens and supports rapid diagnosis and timely treatment decisions.
This code is reported per assay (each), meaning influenza A and influenza B may be reported separately depending on how the test is performed.
Key Facts About CPT® 87400
- Service type: Laboratory test (infectious disease)
- Test: Influenza antigen detection via EIA
- Organisms: Influenza A and/or Influenza B
- Reporting: Per assay (“each”)
- Specimen type: Nasopharyngeal swab, nasal swab, or respiratory specimen
- Provider type: Laboratories, physicians, and qualified healthcare professionals
Common clinical indications:
- Suspected influenza infection
- Acute respiratory illness with fever, cough, or body aches
- Seasonal flu screening in outpatient or urgent care settings
- Evaluation of high-risk patients with respiratory symptoms
When to Use CPT® 87400
CPT 87400 is appropriate when:
- Performing influenza antigen detection using an EIA method
- Testing for influenza A, influenza B, or both
- Rapid identification of influenza infection is needed for clinical decision-making
- The test is not performed using molecular (PCR) methods
Examples:
- Testing a patient with fever and cough during flu season
- Performing rapid influenza screening in an urgent care visit
- Evaluating a high-risk patient with acute respiratory symptoms
- Differentiating influenza from other respiratory infections
Documentation Requirements
To support CPT 87400 billing, documentation should include:
- Patient identifiers and date of service
- Clinical indication for influenza testing
- Specimen source (e.g., nasal or nasopharyngeal swab)
- Test performed (influenza antigen detection via EIA)
- Identification of organism tested (A and/or B)
- Test result and date reported
- Ordering provider information
Clear documentation ensures accurate reporting of each assay performed.
Reimbursement and Coding Considerations
- CPT 87400 is generally covered when medically necessary
- Report per assay (each), influenza A and B may be billed separately if performed independently
- Distinguish from molecular tests (e.g., PCR codes), which use different CPT codes
- May be subject to CLIA waiver requirements depending on the test setting
- Frequency and coverage may vary by payer
Always verify payer-specific infectious disease testing guidelines.
How OptiMantra Supports Infectious Disease Testing
OptiMantra’s integrated EMR and practice management system streamlines documentation and billing for CPT 87400:
With OptiMantra, providers can:
- Document point-of-care or lab-based influenza testing within the patient chart
- Capture test type, organism, and results in structured workflows
- Link results to diagnoses and treatment plans
- Maintain organized laboratory documentation that supports billing compliance and audit preparedness
- Integrate testing workflows into a single, efficient system
By centralizing diagnostic workflows, OptiMantra helps practices improve efficiency, ensure compliance, and optimize reimbursement.
Try OptiMantra for free here!
Disclaimer: CPT® codes are maintained by the American Medical Association. This guide is for informational purposes only and does not replace official coding guidelines or payer policies.
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