A36.89 vs K65
A36.89 (Other diphtheritic complications) compared with K65 (Peritonitis), 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. K65 carries an Excludes1 note covering A36.89: “peritonitis in diphtheria (A36.89)”
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
| A36.89Other diphtheritic complications | K65Peritonitis | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) | K00-K95 — Diseases of the Digestive System (K00-K95) |
| Definition | Other diphtheritic complications is a billable ICD-10-CM diagnosis code (A36.89). | Peritonitis is a non-billable ICD-10-CM category code (K65). |
| Includes | Diphtheritic peritonitis | — |
| Use additional code | — | code (B95-B97), to identify infectious agent, if known |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources