K51 vs K59.3
K51 (Ulcerative colitis) compared with K59.3 (Megacolon, not elsewhere classified), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. K51 carries an Excludes1 note covering K59.3: “megacolon (K59.3-)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| K51Ulcerative colitis | K59.3Megacolon, not elsewhere classified | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | K00-K95 — Diseases of the Digestive System (K00-K95) | K00-K95 — Diseases of the Digestive System (K00-K95) |
| Definition | Ulcerative colitis is a non-billable ICD-10-CM category code (K51). | Megacolon, not elsewhere classified is a non-billable ICD-10-CM category code (K59.3). |
| Includes | noninfective inflammatory bowel disease | Dilatation of colon |
| Use additional code | code to identify any associated fistulas, if applicable: anal fistula (K60.3-) anorectal fistula (K60.5-) | — |
| Code first | — | , if applicable (T51-T65) to identify toxic agent |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources