2027 ICD-10-CM Diagnosis Code C23Malignant neoplasm of gallbladder
ICD-10-CM Codes›C00–D49›C15-C26›C23
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 20
- Chronic Condition
C23 is a billable ICD-10-CM diagnosis code for malignant neoplasm of gallbladder. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 435 through 437. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 21 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - gallbladder.
For Medicare Advantage risk adjustment, C23 maps to CMS-HCC Category 20 (Lung and Other Severe Cancers) under the V28 model, adding a risk factor of about 1.136 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C23 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Carcinoma of gallbladder
- Local recurrence of malignant neoplasm of gallbladder
- Malignant mesenchymal neoplasm of gallbladder
- Malignant neoplasm of gallbladder
- Primary adenocarcinoma of gallbladder
- Primary carcinoma liver and/or biliary system
- Primary carcinoma of gallbladder
- Primary malignant mesenchymal neoplasm of gallbladder
- Primary malignant neoplasm of gallbladder
- Primary squamous cell carcinoma of gallbladder and extrahepatic biliary tract
- Squamous cell carcinoma of gallbladder and extrahepatic biliary tract
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C23: its own notes plus those printed at block C15-C26 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- Kaposi's sarcoma of gastrointestinal sites (C46.4)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- gastrointestinal stromal tumors (C49.A-)
Notes
General instructions on how these codes are used.
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name C23, its category, or a range that includes it.
Applicable To 1
These notes mention C23.
- Z80.0 Family history of malignant neoplasm of digestive organs
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Gallbladder Malignant Neoplasm
a primary or metastatic malignant neoplasm that affects the gallbladder.
Table of NeoplasmsClinical
Patient EducationClinical
Gallbladder Cancer
Your gallbladder is a pear-shaped organ under your liver. It stores bile, a fluid made by your liver to digest fat. As your stomach and intestines digest food, your gallbladder releases bile through a tube called the common bile duct. The duct connects your gallbladder and liver to your small intestine.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C23 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C23Overview
What is the ICD-10 code for malignant neoplasm of gallbladder?
The ICD-10-CM code for malignant neoplasm of gallbladder is C23. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C23 (Malignant neoplasm of gallbladder) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of gallbladder on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C23 group to?
When malignant neoplasm of gallbladder is the principal diagnosis on an inpatient stay, it groups to MS-DRG 436, 437, 435, with relative weights from 0.8078 to 1.8428 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C23 a CC or MCC?
CMS lists C23 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 21 closely related codes in its exclusion list.
Can C23 be reported with C46.4?
Not as a rule. The Excludes1 note at block C15-C26, which applies to C23, lists "Kaposi's sarcoma of gastrointestinal sites (C46.4)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is C23?
C23 (malignant neoplasm of gallbladder) maps to CMS-HCC Category 20 (Lung and Other Severe Cancers), commonly written as HCC 20, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 9 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.
Does C23 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C23 adds a risk adjustment factor of about 1.136 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.672 to 1.214 depending on the payment segment). A more severe related category (HCC 17, HCC 18, and HCC 19) supersedes it when both are reported. See the full factor table on the HCC 20 category page.
