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    v1.0.28
    OpenPayerBilling CodesProcedures / Professional ServicesHCPCS hcpcs-g9321-ct-and-cardiac-nuclear-imaging-prior-study-count
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    HCPCS G9321: Count of Prior CT and Cardiac Nuclear Studies

    HCPCS Level II code G9321 documents the count of prior CT studies (any type) and cardiac nuclear medicine studies (myocardial perfusion or infarct-avid imaging) that are recorded in the 12-month period prior to the current study; the service represents a clinical documentation/billing data capture activity typically performed in radiology or nuclear medicine departments or outpatient imaging centers prior to or concurrent with the current imaging encounter to inform interpretation and patient management.

    For related coverage guidance, see recent payer policy updates: Esophagogastroduodenoscopy (EGD) Coverage Policy, Magnetic Sphincter Augmentation for the Treatment of Gastroesophageal Reflux Disease (GERD), Fecal Analysis in the Diagnosis of Intestinal Dysbiosis and Fecal Microbiota Transplant Testing.

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    Table of contents

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    Clinical & Coding Specifications

    Clinical Context

    A 68-year-old male with a history of coronary artery disease and prior percutaneous coronary intervention presents for a clinically indicated myocardial perfusion study to evaluate ischemia. The imaging department documents the count of prior computed tomography (CT) studies of any type and prior cardiac nuclear medicine studies (myocardial perfusion or infarct-avid imaging) performed within the 12-month period before the current test. Workflow includes review of the electronic medical record and radiology/nuclear medicine information system for prior imaging, verification with the patient and referring provider when needed, and entry of the documented count into the study report and billing record to support use of G9321 for quality and utilization reporting. Typical sites of service are outpatient imaging centers, hospital outpatient departments, and ambulatory cardiac nuclear medicine suites. Common patient scenarios include evaluation of new or recurrent chest pain, assessment of ischemia in patients with prior revascularization, or preoperative cardiac risk assessment.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    78451Myocardial perfusion imaging, tomographic (SPECT), single study; with stress imaging onlyCommon alternative or complementary nuclear medicine method for ischemia assessment performed at same visit
    78452Myocardial perfusion imaging, tomographic (SPECT), multiple studies, at rest and/or redistribution and/or rest and stress; separate reporting for each componentOften performed in conjunction with stress/rest protocols; prior study counts inform interpretation
    75571CT angiography, heart, without contrast, with contrast and image post-processing (coronary CTA)Prior CT counts include coronary CTA when documenting previous imaging in the 12-month lookback
    93740Hemodynamic monitoring during cardiac imaging or stress testing (noninvasive)May be performed during stress imaging sessions; documents physiologic monitoring associated with the study
    93015Cardiovascular stress testing using maximal or submaximal treadmill or bicycle exercise, continuous ECG monitoring, and supervisionPerformed immediately before or during myocardial perfusion imaging for stress acquisition

    Related Modifiers

    8 rows

    ModifierDescriptionWhen to Use
    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…
    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
    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…
    207T00000XNeurological Surgery PhysicianA neurological surgeon provides the operative and non-operative management (i.e., prevention, diagnosis, evaluation, treatment, critical care, and reh…
    363A00000XPhysician AssistantA physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
    363LN0005XCritical Care Neonatal Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
    2279G0305XGeriatric Care Registered Respiratory TherapistCare of older patients who have age and/or disease related decremental pulmonary changes. Diagnosis and treatment is very important for this group si…
    207QB0002XObesity Medicine (Family Medicine) PhysicianA physician who specializes in the treatment of obesity demonstrates competency in and a thorough understanding of the treatment of obesity and the ge…
    364SS0200XSchool Clinical Nurse SpecialistPhysician Assistants & Advanced Practice Nursing Providers · Clinical Nurse Specialist
    225100000XPhysical TherapistPhysical therapists (PTs) are licensed health care professionals who diagnose and treat individuals of all ages, from newborns to the very oldest, who…

    Related ICD-10-CM Codes

    28 rows

    ICD-10-CM CodeDescription
    E11.9Type 2 diabetes mellitus without complications
    E78.5Hyperlipidemia, unspecified
    F33.1Major depressive disorder, recurrent, moderate
    I20.9Angina pectoris, unspecified
    I21.9Acute myocardial infarction, unspecified
    I25.10Atherosclerotic heart disease of native coronary artery without angina pectoris
    I44.2Atrioventricular block, complete
    I46.9Cardiac arrest, cause unspecified
    I48.91Unspecified atrial fibrillation
    I50.9Heart failure, unspecified

    Showing 1–10 of 28

    Related Payer Policy Updates

    Specialty: Gastroenterology1 / 3

    7 rows

    PolicyPayerEffective Date
    Esophagogastroduodenoscopy (EGD) Coverage Policyevicore2026-11-05
    Magnetic Sphincter Augmentation for the Treatment of Gastroesophageal Reflux Disease (GERD)univerahealthcare2026-10-15
    Fecal Analysis in the Diagnosis of Intestinal Dysbiosis and Fecal Microbiota Transplant TestingOscar Health2026-10-01
    Serum Testing for Hepatic Fibrosis in the Evaluation and Monitoring of Chronic Liver DiseaseOscar Health2026-10-01
    Pancreatic Enzyme Testing for Acute PancreatitisOscar Health2026-10-01
    Helicobacter pylori TestingOscar Health2026-10-01
    Celiac Disease TestingOscar Health2026-10-01

    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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