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    OpenPayerBilling CodesProcedures / Professional ServicesHCPCS hcpcs-g1004-clinical-decision-support-national-company-auc
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    HCPCS G1004: Clinical Decision Support Mechanism (National Decision Support Company)

    HCPCS Level II code G1004 describes a clinical decision support mechanism provided by a national decision support company as defined by the Medicare Appropriate Use Criteria program; the service represents an external clinical decision support solution that analyzes imaging or procedural orders and returns appropriateness guidance, typically delivered as a software-as-a-service clinical decision support intervention and used in ambulatory or outpatient imaging and ordering settings to support appropriate use determinations.

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    Table of contents

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    Clinical & Coding Specifications

    Clinical Context

    A primary care physician or ordering clinician uses a certified national clinical decision support (CDS) mechanism to query Appropriate Use Criteria (AUC) at the time of ordering an advanced imaging test (for example CT, MRI, nuclear medicine) for a patient with acute or chronic symptoms. Typical patient scenario: an adult patient presents to outpatient clinic with acute flank pain, suspected renal colic, and hematuria. The clinician enters the imaging order into the electronic health record (EHR), the order triggers a query to the national CDS company using the AUC program, and the CDS returns a guidance response indicating whether the proposed CT abdomen/pelvis without contrast meets AUC. The clinician documents the query response and proceeds with ordering the imaging study when appropriate.

    Typical clinical workflow:

    • Clinician evaluates patient and determines indication for advanced imaging.

    • Clinician places imaging order in the EHR and selects clinical indication.

    • EHR sends a standardized query to the national decision support company (G1004 describes the CDS mechanism service).

    • CDS returns AUC-based decision support result (e.g., “appropriate,” “may be appropriate,” or “rarely appropriate”) and supporting rationale.

    • Clinician documents the CDS response in the patient record, includes any necessary modifier or justification, and finalizes the imaging order.

    Typical site of service: outpatient clinic, ambulatory care centers, hospital outpatient department, or integrated health system EHR ordering environment. Common participating payors include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, BUCA, and Medicare.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    71260Computed tomography, thorax; with contrast materialExample of an advanced imaging study ordered after a CDS consult indicating appropriateness for CT chest
    74177Computed tomography, abdomen and pelvis; with contrast materialCommon CT study ordered for suspected abdominal or pelvic pathology after CDS determination of appropriateness
    72148Magnetic resonance (MR) lumbosacral spine without contrastMRI commonly considered as an alternative imaging modality when CDS suggests MRI rather than CT
    78815Positron emission tomography (PET) imaging, whole bodyAdvanced imaging that may be directed by CDS guidance for oncologic indications
    93000Electrocardiogram, routine ECG with interpretation and report

    Related Modifiers

    7 rows

    ModifierDescriptionWhen to Use
    23Modifier -23 (Unusual Anesthesia) is used on anesthesia service CPT codes when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia…- Use modifier -23 only on anesthesia CPT codes (00100–01999) when a procedure that normally requires no anesthesia or only local anesthesia must be performed under general anesthesia because of…
    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…
    54Modifier ‑54 (“Surgical care only”) is appended to a CPT surgical procedure when the reporting surgeon performs the intraoperative (surgical) component but does not furnish the preoperative and/or…- Use modifier -54 when the reporting surgeon provided only the intraoperative (surgical) component of a procedure and preoperative and/or postoperative management has been or will be provided by…
    55Modifier –55 indicates the billing provider furnished only postoperative management for a procedure that has a global surgical period. According to AAPC, this modifier is appended to the same CPT…- Use modifier -55 when billing the same CPT surgical code that has a 10- or 90-day global period and you, as a provider other than the original surgeon, furnished ONLY postoperative management (no…
    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…
    62Modifier 62 indicates that two surgeons function as co‑surgeons, each performing distinct parts of the same primary surgical procedure. It is appended to the primary procedure code (and any…- Use modifier -62 when two surgeons act as co‑surgeons (both primary surgeons) on a single definitive primary procedure, each performing distinct parts of the same surgical procedure (append -62 to…

    Related Provider Taxonomies

    8 rows

    Taxonomy CodeSpecialtyNotes
    207Q00000XFamily Medicine PhysicianFamily Medicine is the medical specialty which is concerned with the total health care of the individual and the family. It is the specialty in breadt…
    207L00000XAnesthesiology PhysicianAn anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
    208000000XPediatrics PhysicianA pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
    208D00000XGeneral Practice PhysicianA physician who specializes in the general practice of diagnosing, treating, and managing patients with a variety of illnesses and conditions.
    363A00000XPhysician AssistantA physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
    363LX0106XOccupational Health Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
    247000000XHealth Information TechnicianPreferred term for an Accredited Record Technician who is an individual with an associate's degree from an accredited college or independent study pro…
    332BC3200XCustomized Equipment (DME)Suppliers · Durable Medical Equipment & Medical Supplies

    Related ICD-10-CM Codes

    25 rows

    ICD-10-CM CodeDescription
    E11.9Type 2 diabetes mellitus without complications
    E66.9Obesity, unspecified
    E78.5Hyperlipidemia, unspecified
    F41.9Anxiety disorder, unspecified
    G43.909Migraine, unspecified, not intractable, without status migrainosus
    I10Essential (primary) hypertension
    I20.9Angina pectoris, unspecified
    I25.10Atherosclerotic heart disease of native coronary artery without angina pectoris
    I50.9Heart failure, unspecified
    I63.9Cerebral infarction, unspecified

    Showing 1–10 of 25

    Related Codes

    HCPCS-G9490-HOME-ASSESSMENT-NON-HOMEBOUND

    HCPCS G9490: Home Visit Patient Assessment for Non-Homebound Beneficiary

    HCPCS-G0008-INFLUENZA-VACCINE-ADMINISTRATION

    HCPCS G0008: Administration of Influenza Virus Vaccine

    HCPCS-G0009-PNEUMOCOCCAL-VACCINE-ADMINISTRATION

    HCPCS G0009: Administration of Pneumococcal Vaccine

    HCPCS-G0010-HEPATITIS-B-VACCINE-ADMINISTRATION

    HCPCS G0010: Administration of Hepatitis B Vaccine

    HCPCS-G0011-PREP-COUNSELING-HIV-RISK-REDUCTION-ADHERENCE

    HCPCS G0011: Individual PrEP Counseling, HIV Risk Assessment

    HCPCS-G0012-PRE-EXPOSURE-PROPHYLAXIS-INJECTION-HIV-PREVENTION

    HCPCS G0012: Injection of PrEP Drug for HIV Prevention

    HCPCS-G0013-PREP-INDIVIDUAL-COUNSELING-HIV-RISK-REDUCTION

    HCPCS G0013: Individual PrEP Counseling by Clinical Staff

    HCPCS-G0017-PSYCHOTHERAPY-CRISIS-FIRST-60-MINUTES-NON-OFFICE

    HCPCS G0017: Psychotherapy for Crisis, First 60 Minutes

    HCPCS-G0018-PSYCHOTHERAPY-CRISIS-ADDITIONAL-30-MINUTES-NON-OFFICE

    HCPCS G0018: Psychotherapy for Crisis, Additional 30 Minutes

    HCPCS-G0019-COMMUNITY-HEALTH-INTEGRATION-SDOH-CARE-COORDINATION

    HCPCS G0019: Community Health Integration, Person-Centered Assessment

    Showing 1–10 of 1996

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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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    Example of an ancillary diagnostic test that might be ordered in the same workflow but not directly part of the CDS service