Loading...

    Explore
    • Policy Monitoring
    • Live Policy Feed
    • Billing Codes
    • NPI Medicare & Medicaid
    • Healthcare Providers
    • Health Insurance Payers
    • States
    • Service Lines
    • Taxonomy Codes
    Lookup tools
    • Billing Code Lookup
    • CPT Modifier Lookup
    • Provider Taxonomy Code Lookup
    • Healthcare Provider & Facility Lookup
    • Health Insurance Payer Lookup
    • Payer Contact Directory

    Policy & Benchmark Tools

    • Prior Authorization Lookup
    • Coverage Criteria Lookup
    • Timely Filing Lookup
    • Billing Code Reimbursement Rates
    • Payer Comparison Dashboard
    • Facility Comparison Dashboard
    • All tools

    Company

    • About OpenPayer
    • Data Sources
    • Trek Health
    OpenPayerby Trek Health
    LinkedInYouTube

    © 2026 Trek Health. All rights reserved.

    OpenPayer is built and maintained by Trek Health.

    v1.0.28
    OpenPayerBilling CodesHematology and Coagulation ProceduresCPT cpt-85549-plasma-lysozyme-muramidase-assay
    Ask Trek AI about this page

    CPT 85549: Plasma Lysozyme (Muramidase) Assay

    CPT code 85549 describes a laboratory assay measuring muramidase (lysozyme) levels in patient plasma, a clinical chemistry test performed by a lab analyst to evaluate innate immune or granulomatous disease activity; the service is a quantitative enzymatic/plasma protein assay typically provided in a clinical laboratory or hospital laboratory setting.

    For related coverage guidance, see recent payer policy updates: Epithelial Cell Cytology in Breast Cancer Risk Assessment, Chemotherapy Observation or Inpatient Hospitalization (for New Mexico Only), Antibody-Drug Conjugates.

    Customize your policy alerts

    Sign up for cpt 85549 policy alerts

    Get alerted when payer policies referencing 85549 are released or updated.

    Monitor payer policy activity

    Receive email alerts as soon as relevant payer policies are published or updated.

    Table of contents

    Progress1 / 6

    Explore openpayer tools

    • Billing CodesCPT, HCPCS, DRG & more
    • Reimbursement RatesCommercial vs. Medicare rate reports
    • ProvidersHospitals & facilities
    • PayersPlans & market footprint
    • Taxonomy CodesNUCC specialty codes
    • ModifiersCPT modifiers & usage
    • Prior AuthorizationPA policies by payer & drug
    • Timely FilingFiling deadlines by payer
    • Coverage CriteriaMedical necessity by payer
    • Payer ContactsClaims, PA & appeals contacts
    View all tools

    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.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    85610Prothrombin time; plasma or whole bloodRoutine coagulation test often ordered in the same laboratory panel during inpatient evaluations
    85025Blood count; automated complete, CBC with auto differentialCommonly ordered alongside lysozyme testing to assess leukocytosis and differential
    86308Complement; individual component (e.g., C3 or C4)Additional inflammatory marker sometimes ordered with lysozyme in immune-mediated disease workups
    84484Lysozyme (muramidase) — note: 85549 is the specific code for plasma muramidaseClosely related assay; may be used interchangeably in some systems for lysozyme testing

    Related Modifiers

    7 rows

    ModifierDescriptionWhen to Use
    26Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
    90Modifier ‑90 (Reference/Outside Laboratory) indicates that a laboratory test was performed by an entity other than the treating or reporting provider. The American Medical Association defines…- Use CPT modifier -90 when a laboratory test is performed by an outside/reference laboratory (an entity other than the treating or reporting physician or qualified professional) and the claim needs…
    59Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
    52Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
    53Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
    80CPT® Modifier 80 (Assistant Surgeon) is appended to a surgical CPT code when a physician (MD or DO) provides full, continuous assistance throughout the operative procedure. It is intended only for…- Use CPT Modifier -80 when a physician (MD or DO) serves as an assistant surgeon and provides full, continuous assistance throughout the entire operative procedure; append -80 to the surgical CPT…
    91Modifier 91 — “Repeat Clinical Diagnostic Laboratory Test” — is appended when the exact same CPT laboratory test is performed more than once for the same patient on the same day because serial,…- Use modifier 91 when the exact same CPT laboratory test is performed more than once on the same patient on the same date because serial or repeated testing is medically necessary to monitor…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    207RC0000XCardiovascular Disease PhysicianAn internist who specializes in diseases of the heart and blood vessels and manages complex cardiac conditions such as heart attacks and life-threaten…
    207PE0005XUndersea and Hyperbaric Medicine (Emergency Medicine) PhysicianA specialist who treats decompression illness and diving accident cases and uses hyperbaric oxygen therapy to treat such conditions as carbon monoxide…
    229N00000XAnaplastologistAn anaplastologist is a professional who creates prostheses for the face and body. Patients treated include those missing anatomy due to cancer, trau…
    261QM1101XMilitary and U.S. Coast Guard Ambulatory Procedure Clinic/CenterThat part of a "fixed" (non-temporary, non-deployed) DoD or Coast Guard entity furnishing surgical procedures requiring medically supervised recovery.…
    2083C0008XClinical Informatics PhysicianPhysicians who practice Clinical Informatics collaborate with other health care and information technology professionals to analyze, design, implement…
    2251H1300XHuman Factors Physical TherapistRespiratory, Developmental, Rehabilitative and Restorative Service Providers · Physical Therapist
    163WG0100XGastroenterology Registered NurseNursing Service Providers · Registered Nurse
    2080P0006XDevelopmental - Behavioral Pediatrics PhysicianA developmental-behavioral specialist is a pediatrician with special training and experience who aims to foster understanding and promotion of optimal…

    Related Payer Policy Updates

    Specialty: Hematology/Oncology1 / 3

    4 rows

    PolicyPayerEffective Date
    Epithelial Cell Cytology in Breast Cancer Risk AssessmentOscar Health2026-10-01
    Chemotherapy Observation or Inpatient Hospitalization (for New Mexico Only)UnitedHealthcare2026-08-01
    Antibody-Drug ConjugatesPremera Bluecross2026-08-01
    Umbilical Cord Blood Harvesting and Storage for Future Use (for Indiana Only)UnitedHealthcare2026-08-01

    Related Codes

    CPT-85002-BLEEDING-TIME-TEST-LABORATORY

    CPT 85002: Bleeding Time Test, Technical Component

    CPT-85004-AUTOMATED-DIFFERENTIAL-WHITE-BLOOD-CELL-COUNT

    CPT 85004: Automated White Blood Cell Differential

    CPT-85007-MANUAL-DIFFERENTIAL-WHITE-BLOOD-CELL-COUNT

    CPT 85007: Manual Differential White Blood Cell Count

    CPT-85008-BLOOD-SMEAR-MORPHOLOGIC-REVIEW-NO-DIFFERENTIAL

    CPT 85008: Microscopic Blood Smear Examination, No Differential

    CPT-85009-MANUAL-WBC-COUNT-BUFFY-COAT

    CPT 85009: Manual White Blood Cell Count Using Buffy Coat

    CPT-85013-MICROHEMATOCRIT-TEST-LABORATORY-DIAGNOSTIC

    CPT 85013: Microhematocrit Test by Tube Centrifugation

    CPT-85014-HEMATOCRIT-VOLUME-PERCENT-RED-BLOOD-CELLS

    CPT 85014: Hematocrit (Volume Percent of Red Blood Cells)

    CPT-85018-HEMOGLOBIN-ASSAY-WHOLE-BLOOD

    CPT 85018: Hemoglobin Measurement in Whole Blood

    CPT-85025-COMPLETE-BLOOD-COUNT-CBC

    CPT 85025: Complete Blood Count (CBC)

    CPT-85027-COMPLETE-BLOOD-COUNT-HGB-HCT

    CPT 85027: Complete Blood Count with Hemoglobin and Hematocrit

    Showing 1–10 of 99

    • More pages

    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
    Published by

    Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

    Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.