What is ICD-10 code C22.1?

C22.1 is the ICD-10-CM diagnosis code for Intrahepatic bile duct carcinoma. A cancer that develops in the bile ducts inside the liver. This is a rare type of liver cancer distinct from hepatocellular carcinoma. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C22.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C22.1 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C22.1 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C22.1 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for C22.1?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C22.1, V28 maps to Lung and Other Severe Cancers at RAF 1.136 while V24 mapped to Lung and Other Severe Cancers at RAF 1.024. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C22.1?

Ensure documentation confirms intrahepatic location (inside liver) versus extrahepatic bile ducts Note any associated conditions like primary sclerosing cholangitis or liver fluke infection Because C22.1 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM C22.1: Intrahepatic bile duct

ICD-10-CM Code View

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Code lookupC22.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of digestive organs (C15-C26)

C22.1

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Intrahepatic bile duct carcinoma

A cancer that develops in the bile ducts inside the liver. This is a rare type of liver cancer distinct from hepatocellular carcinoma.

Buddy Insight

Intrahepatic cholangiocarcinoma (bile duct carcinoma within the liver) is the second most common primary liver malignancy and is increasing in incidence globally.

CMS-HCC V28

Mapped

HCC 20

Lung and Other Severe Cancers

RAF 1.136

CMS-HCC V24

Mapped

HCC 9

Lung and Other Severe Cancers

RAF 1.024

ACA/HHS

Mapped

HCC 9

HHS-HCC 9

Varies by metal level

ESRD/PACE

Mapped

HCC 9

Lung and Other Severe Cancers

RAF 0.181

RXHCC

Mapped

HCC 20

Cancer, Liver and Intrahepati...

RAF 0.491

Code Book Path

Official

C22Malignant neoplasm of liver and intrahepatic bile ducts

C22.1Intrahepatic bile duct carcinoma

Inclusion Terms

Official

Cholangiocarcinoma

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C22.1 in this effective period.

Related Child Codes

Official

C22.0Liver cell carcinoma

C22.2Hepatoblastoma

C22.3Angiosarcoma of liver

C22.4Other sarcomas of liver

C22.7Other specified carcinomas of liver

Includes

Official

ICD-10-CM does not list Includes notes for C22.1 in this effective period.

Excludes 1

Official

malignant neoplasm of hepatic duct (C24.0)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C22.1 in this effective period.

Use Additional

Official

code to identify:
alcohol abuse and dependence (F10.-)
hepatitis B (B16.-, B18.0-B18.1)
hepatitis C (B17.1-, B18.2)

Code Also

Official

ICD-10-CM does not list Code Also instructions for C22.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathological confirmation of intrahepatic cholangiocarcinoma (bile duct origin within the liver)

Distinction from hepatocellular carcinoma and mixed tumors

Stage of disease

Any associated conditions (primary sclerosing cholangitis, liver fluke infection, hepatolithiasis)

MEAT Support

HCC Buddy guidance

Pathological confirmation of intrahepatic cholangiocarcinoma (bile duct origin within the liver)

Distinction from hepatocellular carcinoma and mixed tumors

Stage of disease

Any associated conditions (primary sclerosing cholangitis, liver fluke infection, hepatolithiasis)

Audit Caution

HCC Buddy guidance

Confusing intrahepatic (C22.1) with extrahepatic (C24.0) cholangiocarcinoma — location determines the code

Coding as hepatocellular carcinoma (C22.0) when pathology shows cholangiocarcinoma histology

Not recognizing Klatskin tumor (perihilar cholangiocarcinoma) as extrahepatic (C24.0), not intrahepatic

Failing to code associated underlying conditions like primary sclerosing cholangitis

Common Mistakes

HCC Buddy guidance

C22.0 — Hepatocellular carcinoma: different cell origin; confirm pathology distinguishes hepatocyte origin from bile duct origin

C24.0 — Extrahepatic bile duct carcinoma: extrahepatic cholangiocarcinoma occurs outside the liver in the common bile duct and hepatic ducts

C22.9 — Liver cancer, not specified: use C22.1 when intrahepatic cholangiocarcinoma is confirmed

C78.7 — Secondary malignant neoplasm of liver: metastatic disease, not primary

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C22.1 an HCC code?

Yes. C22.1 (Intrahepatic bile duct carcinoma) maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24), with a community non-dual aged RAF of 1.136. It is billable for payment year 2026.

Coder answer: C22.1 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C22.1
Description: Intrahepatic bile duct carcinoma
HCC (V28): HCC 20 — Lung and Other Severe Cancers
RAF: 1.136
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers

1.136

V24HCC 9, Lung and Other Severe Cancers

1.024

ESRDHCC 9, Lung and Other Severe Cancers

0.181

RxHCCHCC 20, Cancer, Liver and Intrahepatic Bile Duct

0.491

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work C22.1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C22.1

For C22.1 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C22.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C22.1 is the ICD-10-CM diagnosis code for intrahepatic bile duct carcinoma. A cancer that develops in the bile ducts inside the liver. This is a rare type of liver cancer distinct from hepatocellular carcinoma. C22.1 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of digestive organs (c15-c26).

Under the CMS-HCC V28 risk adjustment model, C22.1 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 1.136. Under the older V24 model, C22.1 mapped to the same category but with a base RAF weight of 1.024, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Ensure documentation confirms intrahepatic location (inside liver) versus extrahepatic bile ducts. Because C22.1 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C22.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Ensure documentation confirms intrahepatic location (inside liver) versus extrahepatic bile ducts
•Note any associated conditions like primary sclerosing cholangitis or liver fluke infection

Clinical Significance

Intrahepatic cholangiocarcinoma (bile duct carcinoma within the liver) is the second most common primary liver malignancy and is increasing in incidence globally. It is a highly aggressive cancer with limited treatment options and a poor prognosis, with five-year survival rates typically below 10% for advanced disease. Accurate distinction from hepatocellular carcinoma and extrahepatic cholangiocarcinoma is critical because treatment approaches differ significantly.

Documentation Requirements

✓Pathological confirmation of intrahepatic cholangiocarcinoma (bile duct origin within the liver)
✓Distinction from hepatocellular carcinoma and mixed tumors
✓Stage of disease
✓Any associated conditions (primary sclerosing cholangitis, liver fluke infection, hepatolithiasis)
✓Molecular markers if tested (isocitrate dehydrogenase mutations, fibroblast growth factor receptor fusions)

Excludes 1, Do NOT code together

malignant neoplasm of hepatic duct (C24.0)

Commonly Confused Codes

•C22.0: Hepatocellular carcinoma: different cell origin; confirm pathology distinguishes hepatocyte origin from bile duct origin
•C24.0: Extrahepatic bile duct carcinoma: extrahepatic cholangiocarcinoma occurs outside the liver in the common bile duct and hepatic ducts
•C22.9: Liver cancer, not specified: use C22.1 when intrahepatic cholangiocarcinoma is confirmed
•C78.7: Secondary malignant neoplasm of liver: metastatic disease, not primary