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.).
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|
36415 | Collection of venous blood by venipuncture | Primary specimen collection method used to obtain whole blood for 0604U testing in outpatient settings. |
99000 | Handling and/or conveyance of specimen for transfer from patient to laboratory (usually bundled) | May be used by some facilities when separately billable specimen handling or courier services are charged in addition to laboratory testing.
82784 | Amino acids, quantitative, plasma or serum, amino acids (Note: not the same analyte) | Represents other quantitative mass spectrometry–based assays; listed as a related lab technology code but not a substitute for the proprietary PLA code 0604U.
0000U | Proprietary Laboratory Analyses example code (placeholder) | Illustrates that PLA tests use unique Category I PLA codes specific to a single manufacturer's test; 0604U is the PLA code for the Virant Diagnostics bradykinin assay.
99213 | Office or other outpatient visit for the evaluation and management of an established patient, moderate complexity | A typical E/M visit during which the clinician documents recurrent angioedema history and orders 0604U testing.