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    v1.0.28
    OpenPayerBilling CodesProcedures / Professional ServicesHCPCS hcpcs-g0121-colonoscopy-screening-average-risk
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    HCPCS G0121: Colorectal Cancer Screening Colonoscopy

    Medicare pays $294 on average nationally for this procedure.

    HCPCS Level II code G0121 represents a colorectal cancer screening colonoscopy performed on an individual who does not meet high‑risk criteria; this preventive procedure is a diagnostic endoscopic service typically provided in an outpatient endoscopy suite or ambulatory surgical center and is used for screening and detection of colorectal neoplasia in average‑risk adults.

    For related coverage guidance, see recent payer policy updates: Esophagogastroduodenoscopy (EGD) Coverage Policy, Magnetic Sphincter Augmentation for the Treatment of Gastroesophageal Reflux Disease (GERD), Serum Testing for Hepatic Fibrosis in the Evaluation and Monitoring of Chronic Liver Disease.

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    Table of contents

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    • Billing CodesCPT, HCPCS, DRG & more
    • Reimbursement RatesCommercial vs. Medicare rate reports
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    • 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
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    Clinical & Coding Specifications

    Clinical Context

    A 58-year-old average-risk patient presents for routine colorectal cancer screening. The patient has no personal or family history of colorectal cancer, polyposis syndromes, inflammatory bowel disease, or high-risk genetic mutations. The primary care physician refers the patient for a screening colonoscopy to be performed in an outpatient endoscopy suite. Pre-procedure evaluation includes a history and physical, medication reconciliation (anticoagulant management if applicable), bowel preparation instructions, and informed consent. On the day of service, the patient receives moderate (conscious) sedation administered and monitored per facility protocol. The endoscopist performs a complete colonoscopic examination to the cecum, documents bowel prep quality, and removes or biopsies any polyps found; if no polyps or suspicious lesions are identified and no high-risk features exist, the service is billed as colorectal cancer screening colonoscopy for an individual not meeting high-risk criteria using billing code G0121. Post-procedure, recovery nursing assesses the patient until discharge criteria are met, and the endoscopist documents findings and recommended surveillance interval according to guidelines.

    Related CPT Codes

    CPT CodeDescriptionRelationship to This Procedure
    45378Colonoscopy, flexible, diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure)Standard diagnostic colonoscopy code often reported for comparable CPT-level services when screening colonoscopy is converted to a diagnostic procedure due to symptoms or removal of lesions.
    45380Colonoscopy, flexible, with biopsy, single or multipleUsed when biopsy specimens are taken during the colonoscopy; may be reported when tissue sampling is performed.
    45385Colonoscopy, flexible, with removal of tumor(s), polyp(s), or other lesion(s) by snare techniqueReported when polyps are removed by snare polypectomy during the colonoscopy.
    45384Colonoscopy, flexible, with directed submucosal injection, any substanceUsed when submucosal injection is performed as part of polypectomy or lesion management.
    00812Anesthesia for lower intestinal endoscopic procedures including colonoscopyAnesthesia code used when general anesthesia or monitored anesthesia care is provided for the colonoscopy; relates to sedation management during the procedure.

    Related Modifiers

    8 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…
    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…
    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…
    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…
    76Modifier -76, Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional, is appended when the same provider performs an identical, medically necessary procedure or…- Use modifier -76 when the same physician or other qualified health care professional performs an identical procedure or service a second (or subsequent) time on the same date of service and the…
    77Modifier 77 indicates that a previously performed procedure or service was legitimately repeated by a different physician or other qualified health care professional. The AMA’s CPT definition…- Use modifier 77 when a basic procedure or service already performed is repeated by a different physician or other qualified health care professional (for example, a second provider independently…
    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
    208000000XPediatrics PhysicianA pediatrician is concerned with the physical, emotional and social health of children from birth to young adulthood. Care encompasses a broad spectru…
    207R00000XInternal Medicine PhysicianA physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
    363L00000XNurse Practitioner(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
    2471V0105XVascular Sonography Radiologic TechnologistA radiologic technologist who specializes in vascular sonography and is trained in the use of ultrasound equipment to image veins and arteries, which …
    261QM1000XMigrant Health Clinic/CenterAmbulatory Health Care Facilities · Clinic/Center
    251B00000XCase Management AgencyAn organization that is responsible for providing case management services. The agency provides services which assist an individual in gaining access…
    3140N1450XPediatric Skilled Nursing FacilityA nursing care facility designed and staffed for the provision of nursing care and appropriate educational and habilitative/rehabilitative services to…
    2086S0129XVascular Surgery PhysicianA surgeon with expertise in the management of surgical disorders of the blood vessels, excluding the intracranial vessels or the heart.

    Related ICD-10-CM Codes

    24 rows

    ICD-10-CM CodeDescription
    D01.0Carcinoma in situ of colon
    D12.0Benign neoplasm of cecum
    D12.6Benign neoplasm of colon, unspecified
    D12.7Benign neoplasm of rectosigmoid junction
    K50.90Crohn's disease, unspecified, without complications
    K51.90Ulcerative colitis, unspecified, without complications
    K57.20Diverticulitis of large intestine with perforation and abscess without bleeding
    K57.30Diverticulosis of large intestine without perforation or abscess without bleeding
    K58.9Irritable bowel syndrome, unspecified
    K63.5Polyp of colon

    Showing 1–10 of 24

    Related Payer Policy Updates

    Specialty: Gastroenterology1 / 3

    10 rows

    PolicyPayerEffective Date
    Esophagogastroduodenoscopy (EGD) Coverage Policyevicore2026-11-05
    Magnetic Sphincter Augmentation for the Treatment of Gastroesophageal Reflux Disease (GERD)univerahealthcare2026-10-15
    Serum Testing for Hepatic Fibrosis in the Evaluation and Monitoring of Chronic Liver DiseaseOscar Health2026-10-01
    Fecal Analysis in the Diagnosis of Intestinal Dysbiosis and Fecal Microbiota Transplant TestingOscar Health2026-10-01
    Pancreatic Enzyme Testing for Acute PancreatitisOscar Health2026-10-01
    Helicobacter pylori TestingOscar Health2026-10-01
    Celiac Disease TestingOscar Health2026-10-01
    Laboratory Testing for the Diagnosis of Inflammatory Bowel DiseaseOscar Health2026-10-01
    Percutaneous Electrical Nerve Field Stimulation (PENFS)Cigna2026-09-15
    Colorectal Cancer ScreeningBlue Cross Blue Shield - New Mexico2026-09-04

    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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