Summary & Overview
CPT 0604U: Bradykinin Quantitative Assay by LC–MS/MS
CPT code 0604U is a Proprietary Laboratory Analyses (PLA) code that identifies a single, manufacturer-specific laboratory test: quantitative measurement of four bradykinin peptides in whole blood by liquid chromatography–tandem mass spectrometry (LC–MS/MS) from Virant Diagnostics Inc. The assay has clinical relevance for evaluating disorders such as chronic recurrent angioedema where bradykinin pathways are implicated. Nationally, PLA codes like 0604U matter because they permit distinct identification of novel or proprietary assays for coverage, claims processing, and utilization tracking.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise review of the clinical context for the assay, the service setting and specimen type, and the implications of a PLA-designated CPT code for payer recognition and coding precision. The publication covers expected benchmarks for coding and billing adoption, potential policy considerations around proprietary diagnostics, and how the code fits into laboratory service lines and clinical workflows. Data not available in the input for payer-specific coverage policies, modifiers, taxonomies, ICD-10 pairings, or related codes is explicitly noted as unavailable, and readers will be directed to payer policies for specific coverage rules.
Billing Code Overview
CPT code 0604U is a Proprietary Laboratory Analyses (PLA) code that applies exclusively to a single laboratory test: Bradykinin, Quantitative, by LC–MS/MS from Virant Diagnostics Inc. The test quantitatively measures four bradykinin peptides in whole blood using liquid chromatography with tandem mass spectrometry (LC–MS/MS). Results support clinical assessment of disorders such as chronic recurrent angioedema.
Service Type: Proprietary laboratory molecular diagnostic test (PLA)
Typical Site of Service: Clinical laboratory or reference laboratory; specimen collected in an outpatient or inpatient setting as appropriate for laboratory testing.
Clinical & Coding Specifications
Clinical Context
A 38-year-old patient presents to an allergy/immunology clinic with a history of recurrent, nonpruritic angioedema episodes affecting the face and extremities over several months. Routine allergy testing and C1 esterase inhibitor studies were inconclusive. The treating allergist orders a specialized biochemical assay to quantify circulating bradykinin peptides to evaluate for bradykinin-mediated angioedema. A whole blood specimen is collected in the outpatient clinic and sent to Virant Diagnostics Inc. for the proprietary test reported with 0604U (Bradykinin, Quantitative, by LC–MS/MS). The laboratory performs liquid chromatography–tandem mass spectrometry analysis of four bradykinin peptides and returns a numeric report with peptide concentrations and interpretive comments. Results are reviewed by the ordering clinician to support diagnosis of chronic recurrent angioedema subtypes and guide further management decisions, such as considering targeted therapies or referral to specialized clinics. Typical site of service is outpatient clinic or outpatient phlebotomy with testing performed at the reference laboratory (Virant Diagnostics Inc.).
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use if reporting a separate professional component for test interpretation when applicable (rare for proprietary reference lab tests performed entirely by the laboratory). |
| Distinct procedural service | Use if reporting a separate service on the same day that is distinct and not incidental to the lab test (typically not appended to PLA lab codes but may apply to associated specimen collection services).