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    v1.0.28
    OpenPayerBilling CodesMedical And Surgical SuppliesHCPCS hcpcs-a4590-special-casting-material-fiberglass
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    HCPCS Level II A4590: Special Casting Material (fiberglass)

    HCPCS Level II code A4590 describes special casting material, such as fiberglass, used to fabricate or reinforce orthopedic casts and splints as part of durable medical equipment and immobilization services; the service type is casting material supply, typically provided in outpatient clinics, orthopedic offices, emergency departments, and durable medical equipment supplier settings.

    For related coverage guidance, see recent payer policy updates: Salivary Hormone Testing, Parathyroid Hormone, Phosphorus, Calcium, and Magnesium Testing, Bone Turnover Markers Testing.

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    Clinical & Coding Specifications

    Clinical Context

    A typical patient is an adult or pediatric individual presenting to an orthopedic clinic, urgent care, or emergency department with an acute extremity fracture, severe sprain, or postoperative requirement for a definitive or temporary immobilization. The clinician evaluates the injury with history, physical exam, and plain radiographs. When immobilization using a molded, lightweight, radiolucent cast is indicated, the provider applies a special casting material such as A4590 (fiberglass). The workflow includes wound/skin assessment, measurement and trimming of stockinette and padding, application of fiberglass rolls or splint components, molding for appropriate immobilization and circulation, and patient instruction on cast care and follow-up. Typical sites of service are outpatient orthopedic clinic, ambulatory surgical center, emergency department, urgent care, and inpatient hospital units when conversion from plaster to fiberglass or postoperative immobilization is needed.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    29075Application of short arm cast (forearm and wrist)Commonly precedes or follows fiberglass material application for forearm/wrist immobilization.
    29515Application of short leg cast (below knee)Used when A4590 fiberglass is utilized to immobilize lower extremity injuries.
    29065Application of long arm cast (including shoulder to hand)Applied when immobilization requires fiberglass for longer upper extremity casts.
    20690Removal of deep implant (separate procedure)May precede casting in postoperative patients when hardware removal and subsequent immobilization are required.
    99070Supplies and materials (non-physician)Used to bill additional non-covered supplies related to cast application when payer requires separate supply billing.

    Related Modifiers

    6 rows

    ModifierDescriptionWhen to Use
    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…
    56Modifier ‑56 indicates the reporting provider furnished only the preoperative management for a surgical procedure and did not perform the intraoperative or postoperative care. It is used in…- Use Modifier -56 when a provider performs only the preoperative management in a split‑care situation (one physician manages preop care while a different physician performs the intraoperative…
    78CPT modifier -78 indicates an unplanned, related return to the operating or procedure room by the same provider during the global postoperative period. It is appended when treatment for a…- Use modifier -78 when an unplanned, related complication during the original procedure’s global postoperative period requires the patient to return to a formal operating or procedure room and the…
    22Modifier –22 (Increased Procedural Services) is used when a reported procedure is substantially more extensive than normally required. The CPT Manual and CMS state it may be appended only when the…- When to use: Append modifier -22 to a procedural CPT code when the service performed is substantially more extensive than the usual service described by that code — i.e., the procedure required…
    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…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    207L00000XAnesthesiology PhysicianAn anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
    207K00000XAllergy & Immunology PhysicianAn allergist-immunologist is trained in evaluation, physical and laboratory diagnosis, and management of disorders involving the immune system. Select…
    207P00000XEmergency Medicine PhysicianAn emergency physician focuses on the immediate decision making and action necessary to prevent death or any further disability both in the pre-hospit…
    363A00000XPhysician AssistantA physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
    364SA2100XAcute Care Clinical Nurse SpecialistPhysician Assistants & Advanced Practice Nursing Providers · Clinical Nurse Specialist
    1223D0004XDental AnesthesiologyA dentist who has successfully completed an accredited postdoctoral anesthesiology residency training program for dentists of two or more years durati…
    283X00000XRehabilitation HospitalA hospital or facility that provides health-related, social and/or vocational services to disabled persons to help them attain their maximum functiona…
    207RI0008XHepatology PhysicianThe discipline of Hepatology encompasses the structure, function, and diseases of the liver and biliary tract. The American Board of Internal Medicine…

    Related Payer Policy Updates

    Specialty: Endocrinology1 / 3

    10 rows

    PolicyPayerEffective Date
    Salivary Hormone TestingOscar Health2026-10-01
    Parathyroid Hormone, Phosphorus, Calcium, and Magnesium TestingOscar Health2026-10-01
    Bone Turnover Markers TestingOscar Health2026-10-01
    Testosterone — Coverage Criteria for Measurement and MonitoringOscar Health2026-10-01
    Diabetes Mellitus Testing — Coverage CriteriaOscar Health2026-10-01
    Thyroid Disease TestingOscar Health2026-10-01
    Thyroid Disease Testingblue cross blue shield - louisiana2026-09-15
    Thyroid Disease TestingBlue Cross Blue Shield - New Mexico2026-09-04
    Parathyroid Hormone, Phosphorous, Calcium and Magnesium TestingBlue Cross Blue Shield - New Mexico2026-09-04
    Testosterone laboratory testing and managementPremera Bluecross2026-09-04

    Related Codes

    HCPCS-A4206-STERILE-SYRINGE-1CC-NEEDLE

    HCPCS A4206: Syringe with Needle, 1 cc or Less, Sterile

    HCPCS-A4207-STERILE-2CC-SYRINGE-WITH-NEEDLE

    HCPCS Level II A4207: Syringe with Needle, Sterile 2 cc

    HCPCS-A4208-STERILE-3CC-SYRINGE-WITH-NEEDLE

    HCPCS Level II A4208: Syringe with Needle, Sterile 3 cc

    HCPCS-A4209-STERILE-SYRINGE-WITH-NEEDLE-5CC-OR-GREATER

    HCPCS Level II A4209: Syringe with Needle, Sterile 5 cc or Greater

    HCPCS-A4210-NEEDLE-FREE-INJECTION-DEVICE

    HCPCS Level II A4210: Needle-free Injection Device, Each

    HCPCS-A4211-SUPPLIES-SELF-ADMINISTERED-INJECTIONS

    HCPCS Level II A4211: Supplies for Self-Administered Injections

    HCPCS-A4212-NON-CORING-NEEDLE-STYLET-CATHETER-ACCESS-SUPPLY

    HCPCS Level II A4212: Non-coring Needle or Stylet with/without Catheter

    HCPCS-A4213-STERILE-SYRINGE-20CC-OR-GREATER

    HCPCS Level II A4213: Syringe, Sterile, 20 cc or Greater, Each

    HCPCS-A4215-STERILE-NEEDLE-SINGLE-EACH

    HCPCS Level II A4215: Needle, Sterile, Any Size

    HCPCS-A4216-STERILE-DILUENT-FLUSH-10ML

    HCPCS Level II A4216: Sterile Diluent/Flush, 10 ml

    Showing 1–10 of 633

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    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.
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