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G0121

PAYER POLICY CHANGES

G0121 Insurance Policy Changes

HCPCS G0121 is officially defined as "Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk." HCPCS G0121 is referenced in 16 tracked payer policy changes from Medicare/CMS - Transmittals, Aetna, and 4 other payers. For billers and coders, staying current on payer-specific coverage criteria, reimbursement rules, and prior-authorization requirements for HCPCS G0121 is critical to clean claim submission. Each entry below links to the full policy analysis with effective dates and action steps.

Medicare/CMS - Transmittals · Effective Nov 16, 2026Low impact
R13912CP: Internet-Only Manual (IOM) Update(s) to Publication 100-04, Chapter 23, Section(s) 20.3, 20.4, 20.8 and Addendum - Medicare Physician Fee Schedule Database (MPFSDB) File Record Layout and Field Descriptions
All HCPCS Level II codes remain effective until CMS announces otherwise, and they are not designated as temporary or permanent. The Medicare Physician Fee Schedule Database (MPFSDB) file layout is revised to accommodate two different conversion factors under the Quality Payment Program. The updates apply to Medicare Claims Processing Manual Chapter 23 sections 20.3, 20.4 and 20.8 and the MPFSDB addendum, with an effective date of November 16, 2026 and a date-of-service effective date unless otherwise specified.
Medicare/CMS - Transmittals · Effective Jun 8, 2026High impact
R13921CP: NCD 210.3 Screening for Colorectal Cancer-Non-Invasive Biomarker Tests
CMS determined that, effective June 8, 2026, non-invasive biomarker colorectal cancer screening tests are covered for Medicare beneficiaries under NCD 210.3 when they meet specific criteria. Covered tests are limited to once every three years for asymptomatic, average-risk patients aged 45 to 85, and the test must be FDA market authorized and indicated for colorectal cancer screening, processed in a CLIA certified laboratory, and meet defined sensitivity and specificity thresholds. The transmittal adds ColoSense (0421U) as a covered screening test and sets an implementation date of January 4, 2027 for the claims processing changes.
Aetna · Effective Jul 1, 2025High impact
OfficeLink Updates - April 2025 notices and reminders (PDF)
Aetna updated their National Precertification List with multiple new drug requirements and removed precertification for BRCA genetic testing. Several new specialty drugs now require precertification with staggered effective dates from March through April 2025, and new claim edits will be implemented starting July 1, 2025.
Medical Mutual of Ohio · Identified Jun 20, 2026High impact
Coding Follow-Up Colonoscopies Correctly for Medicare Advantage Members
Medicare Advantage members must have follow-up colonoscopies after positive stool-based tests coded as screening (G0105/G0121) with modifier KX to ensure $0 member cost-sharing. If biopsy/polypectomy is performed during the same visit, append modifier PT to the therapeutic CPT code as secondary.
Regence BlueShield · Effective Nov 1, 2026Medium impact
Surgical Site of Care - Colonoscopy and Sigmoidoscopy
Effective November 1, 2026, the Surgical Site of Care policy for colonoscopy and sigmoidoscopy codes applies site of care medical necessity review only when the procedure is performed in an outpatient hospital setting. Use of a hospital outpatient department instead of an ambulatory surgery center or physician office may be considered medically necessary when one or more listed criteria are met, such as no geographically accessible in-network ASC that has the necessary equipment, a procedure that requires discontinuing medications that necessitate inpatient monitoring, ASA Physical Status III or higher, or a BMI over 40. When none of the criteria are met, hospital outpatient use is considered not medically necessary.
Regence BlueShield · Effective Nov 1, 2026Medium impact
Surgical Site of Care - Colonoscopy
Effective November 1, 2026, use of a hospital outpatient department instead of an ambulatory surgery center or physician office for surgical services may be considered medically necessary when one of the listed criteria is met, such as no geographically accessible in-network ASC within 25 miles of the individual's residence that has the necessary equipment, a procedure that requires discontinuing medications that necessitate inpatient monitoring, an American Society of Anesthesiologists Physical Status classification of III or higher, a body mass index over 40, or a prolonged surgery over 3 hours. Site of care medical necessity reviews apply to the listed colonoscopy, sigmoidoscopy and colorectal screening codes only when they are performed in an outpatient hospital setting, and use of a hospital outpatient department when the criteria are not met is considered not medically necessary.
Independence Blue Cross · Effective Jul 1, 2026Medium impact
11.03.12w, Colorectal Cancer Screening
Independence Blue Cross changed Cologuard Plus coverage from experimental/investigational to medically necessary effective 07/01/2026. CPT code 0464U (colorectal cancer screening with methylated DNA markers) is now covered. Billing teams must update claims processing to reflect this code as medically necessary rather than denying it as experimental.
Blue Cross & Blue Shield of Mississippi · Effective Oct 1, 2025Medium impact
Colonoscopy, Flexible Sigmoidoscopy and CT Colonography
For asymptomatic individuals, screening colonoscopy and sigmoidoscopy are covered beginning at age 45, effective 01/01/2022. Men and women should follow one of two options, flexible sigmoidoscopy every 5 years or colonoscopy every 10 years, and a digital rectal examination should be performed at each screening, with earlier or more frequent screening for high-risk individuals as determined by the ordering physician. CT colonography may be medically necessary only when a conventional colonoscopy is indicated but cannot be completed for medical reasons or is incomplete because of colonic stenosis or obstruction, and it is considered not medically necessary for colon cancer screening otherwise.
Independence Blue Cross · Effective Jul 1, 2025Medium impact
11.03.12v, Colorectal Cancer Screening
Independence Blue Cross removed barium enema from covered colorectal cancer screening tests effective 07/01/2025, aligning with 2018 American Cancer Society and 2024 American College of Radiology guidelines. Additionally, two new tests (BeScreened-CRC and FirstSight CRC) were classified as experimental/investigational and are no longer covered.
Aetna · Identified Nov 7, 2026Medium impact
In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2026-10-27)
Aetna's Clinical Policy Bulletin 0783 (reviewed 2026-10-27) confirms that in vivo analysis technologies for gastrointestinal and urothelial lesions, including confocal laser endomicroscopy, narrow-band imaging, chromoendoscopy and optical biopsy systems, are considered experimental, investigational or unproven for the listed indications. Claims for these services with the listed CPT codes (such as 43206, 43252 and +0397T) and ICD-10 diagnoses will be denied under this policy, so billing staff should review how these services are coded and documented before submission.
Aetna · Identified Oct 30, 2026Medium impact
In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2026-10-26)
Aetna Clinical Policy Bulletin 0783 addresses in vivo analysis of gastrointestinal and urothelial lesions. It considers confocal laser endomicroscopy, including Cellvizio probe-based confocal laser endomicroscopy, and in-vivo analysis of colorectal polyps experimental, investigational, or unproven for the indications listed, because the effectiveness of these approaches has not been established. The source lists CPT and ICD-10 codes as not covered for the indications in the policy and gives a last review date of 10/26/2026.
Aetna · Identified Oct 2, 2026Medium impact
Colonoscopy, Colorectal Cancer Screening, and Related Procedures (CPB 0516, reviewed 2026-08-20)
Aetna Clinical Policy Bulletin 0516 sets the coverage rules for colonoscopy, colorectal cancer (CRC) screening and related procedures. For average-risk members aged 45 and older whose physician recommends screening, Aetna considers medically necessary colonoscopy every 10 years, CT colonography every 5 years, annual FIT or FOBT, flexible sigmoidoscopy every 5 years (or every 10 years when combined with an annual FIT or FOBT), and stool DNA tests (FIT-DNA, Cologuard, Cologuard Plus) every 1 to 3 years. Colonoscopy or sigmoidoscopy is considered medically necessary as frequently as every 2 years for members with specified high-risk factors, and surveillance is considered medically necessary as frequently as every year for inflammatory bowel disease or a personal history of CRC and every 2 years for a personal history of adenomatous polyps. Aetna considers double contrast barium enema not medically necessary for screening, high-risk testing, surveillance and diagnostic testing, and considers AI-aided colonoscopy, Guardant Shield, and several other blood, stool and imaging-based screening methods experimental, investigational or unproven.
Aetna · Identified Aug 19, 2026Medium impact
In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2025-12-11)
Aetna Clinical Policy Bulletin 0783 considers confocal laser endomicroscopy (including Cellvizio probe-based confocal laser endomicroscopy) experimental, investigational, or unproven for the indications it lists, because the effectiveness of these approaches has not been established. The listed indications include assessment of safe surgical margins during laryngectomy, confirmation of low-grade dysplasia and surveillance of Barrett's esophagus, diagnosis and histologic grading of bladder cancer, diagnosis and staging of lung cancer, diagnosis of prostate cancer, diagnosis of head and neck squamous cell carcinoma, differentiation of colorectal polyps during routine colonoscopy, and diagnosis of indeterminate biliary strictures and pancreatic lesions. The policy also lists elastic-scattering spectroscopy for colonic polyps, ERCP with optical endomicroscopy for biliary lesions, and in vivo analysis of colorectal polyps (including chromoendoscopy, endocytoscopy, narrow-band imaging, multi-band imaging and the Optical Biopsy System) as experimental, investigational, or unproven.
Aetna · Identified Aug 19, 2026Medium impact
Virtual Gastrointestinal Endoscopy (CPB 0535, reviewed 2026-07-30)
Aetna covers CT colonography, also called virtual colonoscopy, every 5 years as a colorectal cancer screening for average-risk asymptomatic members aged 45 or older. Diagnostic virtual colonoscopy is covered for symptomatic members with a known colonic obstruction when standard colonoscopy is contraindicated, an incomplete colonoscopy, chronic anticoagulation that cannot be interrupted, complications from a prior colonoscopy, active diverticulitis with increased risk of perforation, increased sedation risk, or symptoms requiring colon examination less than 12 weeks after colon surgery. Aetna considers virtual colonoscopy experimental, investigational, or unproven for all other indications, including screening, diagnosis or surveillance of colorectal cancer in people without a known colonic obstruction or an incomplete optical colonoscopy, and for Lynch syndrome, and considers MRI colonography and CT-based virtual upper GI endoscopy experimental, investigational, or unproven as well. Aetna considers magnetic resonance enterography medically necessary for monitoring known inflammatory bowel disease, in particular Crohn's disease, when small bowel disease or penetrating disease complications are present.
Aetna · Identified Aug 15, 2026Medium impact
Colonoscopy, Colorectal Cancer Screening, and Related Procedures (CPB 0516, reviewed 2025-11-12)
Aetna considers colorectal cancer screening medically necessary for average-risk members aged 45 years and older when their physician recommends it, with colonoscopy every 10 years, CT colonography every 5 years, annual FIT or FOBT, flexible sigmoidoscopy every 5 years, flexible sigmoidoscopy every 10 years when combined with annual FIT or FOBT, and stool DNA every 1 to 3 years. Colonoscopy or sigmoidoscopy as frequently as every 2 years is considered medically necessary for members with a first-degree relative who had CRC or adenomatous polyps, familial adenomatous polyposis, hereditary non-polyposis CRC, MYH-associated polyposis in siblings, or Cowden syndrome, and surveillance is considered medically necessary as frequently as every year for inflammatory bowel disease or a personal history of CRC. Double contrast barium enema is not considered medically necessary, and AI-aided colonoscopy, blood-based biomarkers, Guardant Shield, stool-based protein biomarkers, fecal volatile organic compound analysis, anal Pap smear, drug-coated balloons for colonic strictures, and the full-thickness resection device for appendiceal polyps are considered experimental, investigational or unproven.
Aetna · Identified Jun 19, 2026Medium impact
OfficeLink Updates - October 2024 notices and reminders (PDF)
Already effective between September 2, 2024 and January 1, 2025: precertification is required for Winrevair, Hercessi, Imdelltra, Rytelo, Yesafili, Opuviz, Ahzantive, Piasky, Kisunla, Yimmugo, Nypozi, Bkemv and Epysqli, and precertification is no longer required for Medicare members for Durolane, Euflexxa, Synvisc, Synvisc-One, Firmagon, Eligard and Zarxio effective October 1, 2024. Effective January 1, 2025, pathology codes 88300-88309 and 88331-88334 deny when billed on the same date of service as Mohs micrographic surgery codes 17311-17315, professional claims with a PC/TC indicator of '= 5' are not payable for hospital inpatients or patients in a hospital outpatient department, and Cologuard performed within one year after a completed colonoscopy will be denied. Also effective January 1, 2025, pharmacogenomic panel claims for Medicare members must be billed with CPT 81418, and Aetna International stateside members with a United States service address join the Enhanced Clinical Review Program for commercial members.

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REFERENCE DATA

Payers with rules2

Payers requiring prior auth2

CalViva Health · Effective December 31, 2025
Prior authorization required
CalViva Health CMS-0057-F prior authorization requirements
Community Health Plan of Imperial Valley · Effective December 31, 2025
Prior authorization required
Community Health Plan of Imperial Valley CMS-0057-F prior authorization requirements

FREQUENTLY ASKED QUESTIONS

Does CalViva Health require prior authorization for G0121?

CalViva Health lists G0121 on CalViva Health CMS-0057-F prior authorization requirements for medicaid managed plans (list dated December 31, 2025). Verify with the payer before scheduling.

Does Community Health Plan of Imperial Valley require prior authorization for G0121?

Community Health Plan of Imperial Valley lists G0121 on Community Health Plan of Imperial Valley CMS-0057-F prior authorization requirements for medicaid managed plans (list dated December 31, 2025). Verify with the payer before scheduling.

What insurance policy changes affect HCPCS G0121?

There are 16 tracked policy changes affecting HCPCS G0121, including updates from Medicare/CMS - Transmittals, Aetna, Medical Mutual of Ohio. Each change may modify coverage criteria, reimbursement rates, or prior-authorization requirements.

Which payers have updated policy for HCPCS G0121?

Payers that have issued tracked updates for HCPCS G0121 include: Medicare/CMS - Transmittals, Aetna, Medical Mutual of Ohio, Regence BlueShield, Independence Blue Cross, Blue Cross & Blue Shield of Mississippi.

How do I get notified when HCPCS G0121 policy changes?

Create a free account at PolicyChanges.app and save a search filtered to HCPCS G0121. You will get an email when new policy changes reference this code: daily or weekly, your choice, on every plan.

Why do payers change policies for HCPCS G0121?

Payers revise policies for individual billing codes to align with updated clinical guidelines, CMS rule changes, fraud and abuse prevention measures, or network cost-management goals. Changes can affect medical necessity criteria, place-of-service restrictions, bundling rules, or whether a code requires prior authorization.

See every payer rule for G0121

Prior authorization lists, coverage criteria, NCCI edits and Medicare coverage articles for G0121 in one place.

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All billing codes J3590 C9399 J3490 99215 99213 99202

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R13912CP: Internet-Only Manual (IOM) Update(s) to Publication 100-04, Chapter 23, Section(s) 20.3, 20.4, 20.8 and Addendum - Medicare Physician Fee Schedule Database (MPFSDB) File Record Layout and Field Descriptions

R13921CP: NCD 210.3 Screening for Colorectal Cancer-Non-Invasive Biomarker Tests

OfficeLink Updates - April 2025 notices and reminders (PDF)

Coding Follow-Up Colonoscopies Correctly for Medicare Advantage Members

Surgical Site of Care - Colonoscopy and Sigmoidoscopy

Surgical Site of Care - Colonoscopy

11.03.12w, Colorectal Cancer Screening

Colonoscopy, Flexible Sigmoidoscopy and CT Colonography

11.03.12v, Colorectal Cancer Screening

In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2026-10-27)

In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2026-10-26)

Colonoscopy, Colorectal Cancer Screening, and Related Procedures (CPB 0516, reviewed 2026-08-20)

In Vivo Analysis of Gastro-Intestinal and Urothelial Lesions (CPB 0783, reviewed 2025-12-11)

Virtual Gastrointestinal Endoscopy (CPB 0535, reviewed 2026-07-30)

Colonoscopy, Colorectal Cancer Screening, and Related Procedures (CPB 0516, reviewed 2025-11-12)

OfficeLink Updates - October 2024 notices and reminders (PDF)

Prior authorization required