Summary & Overview
CPT 85549: Plasma Lysozyme (Muramidase) Assay
CPT code 85549 reports a plasma assay for muramidase, commonly known as lysozyme. This laboratory procedure quantifies lysozyme levels in plasma to aid clinical assessment of immune activation and to support evaluation of hematologic, infectious, and certain granulomatous disorders. As a specialized clinical chemistry test, it is performed in certified clinical or hospital laboratories and carries implications for diagnostic workups and disease monitoring.
Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The content outlines what the code represents, the typical setting where the service is delivered, and payer relevance for coverage and billing practice.
Readers will learn the clinical context for ordering a lysozyme assay, the typical laboratory service model and site of service, and practical billing considerations tied to CPT code 85549. Where available, discussions include benchmark considerations and policy-relevant factors that affect reimbursement and claims processing. Data not available in the input for specific modifiers, associated taxonomies, ICD-10 diagnoses, related codes, and payer-specific rates are noted as unavailable.
Billing Code Overview
CPT code 85549 describes a laboratory test in which a lab analyst measures the level of muramidase (lysozyme) in patient plasma. This test evaluates the concentration of lysozyme, an enzyme associated with immune activity and certain hematologic, infectious, and granulomatous conditions.
Service type: Clinical laboratory test — plasma analyte assay
Typical site of service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A 56-year-old patient with a history of chronic granulomatous inflammation presents with persistent unexplained leukocytosis, low-grade fever, and splenomegaly. The clinician orders a plasma muramidase (lysozyme) assay to evaluate for macrophage activation syndrome, sarcoidosis, or monocytic/myelomonocytic leukemias where serum lysozyme can be elevated. The typical workflow: a phlebotomist collects a plasma sample in the outpatient laboratory or hospital inpatient unit; the specimen is processed by the clinical laboratory, and a lab analyst performs the 85549 quantitative muramidase (lysozyme) assay. Results are reported to the ordering clinician and integrated with other inflammatory markers and hematology findings to guide further diagnostic evaluation or monitoring.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When the physician provides the professional interpretation separate from the technical lab work |
90 | Reference laboratory | When the specimen is sent to an outside reference laboratory for testing |