Is ICD-10-CM code C66 billable?

No, C66 (Malignant neoplasm of ureter) 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 C66 belong to?

C66 belongs to Chapter 2 of the ICD-10-CM tabular list: C00–D49 (Neoplasms).

C66Not billable, use a more specific code below

Malignant neoplasm of ureter

In Malignant neoplasms of urinary tract (C64-C68), chapter 2: Neoplasms

3 billable codes under C66: 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 neoplasm of ureteric orifice of bladder (C67.6)

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 C66

C66 can't be used on a claim. Pick a billable code below; grey headings group them.

C66 MS-DRGs

As the principal diagnosis, all 3 billable codes under C66 group to MS-DRG 656, 657, 658, 686, 687, or 688 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

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

Cancer

Cancer is not just one disease but many diseases. Cancer begins in your cells, which are the building blocks of your body. Usually, your body forms new cells as needed, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor.

Ureteral Disorders

Your kidneys make urine by filtering wastes and extra water from your blood. The urine travels from the kidneys to the bladder in two thin tubes called ureters.

Code history

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