Is ICD-10-CM code C18 billable?

No, C18 (Malignant neoplasm of colon) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code C18 belong to?

C18 belongs to Chapter 2 of the ICD-10-CM tabular list: C00–D49 (Neoplasms).

C18Not billable, use a more specific code below

Malignant neoplasm of colon

In Malignant neoplasms of digestive organs (C15-C26), chapter 2: Neoplasms

10 billable codes under C18: all are a CC; all map to HCC 22 (Bladder, Colorectal, and Other Cancers).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Excludes1: not coded here, use a different code

malignant carcinoid tumors of the colon (C7A.02-)

Also applies, from Malignant neoplasms of digestive organs (C15-C26)

These notes sit on C15-C26 and apply to every code under it, including C18.

Excludes1: not coded here, use a different code

Kaposi's sarcoma of gastrointestinal sites (C46.4)

Excludes2: not included here, code separately if applicable

gastrointestinal stromal tumors (C49.A-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Rules for coding benign and malignant neoplasms: using the Neoplasm Table, sequencing primary and secondary sites, treatment encounters, complications, and current cancer versus personal history.

Admission/Encounter for treatment of primary site (page 33)
Admission/Encounter for treatment of secondary site (page 33)
Coding and sequencing of complications (page 34)
Primary malignancy previously excised (page 34)
Admissions/Encounters involving antineoplastic chemotherapy, immunotherapy and radiation therapy (page 35)
Admission/encounter to determine extent of malignancy (page 36)
Symptoms, signs, and abnormal findings listed in Chapter 18 associated with neoplasms (page 36)
Admission/encounter for pain control/management (page 36)

Read Section I.C.2 (page 32), 12 more topics

All codes under C18

C18 can't be used on a claim. Pick a billable code below; grey headings group them.

C18 MS-DRGs

As the principal diagnosis, all 10 billable codes under C18 group to MS-DRG 374, 375, or 376 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to C18

Notes on these codes point to C18.

D13.91 Code Also: malignant neoplasm of colon (C18.-)
Z85.038 Includes: Conditions classifiable to C18

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Colorectal Cancer

Colorectal cancer is cancer that develops in the tissues of the colon or rectum. Your colon and rectum are part of your digestive system: Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer that affects either of these parts may also be called colorectal cancer.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.