ICD-10-CM 2027
ICD-10 code for appendix disease
From the official ICD-10-CM alphabetic index entry “Disease, diseased › appendix”. Page updated September 29, 2026.
About coding appendix disease
The ICD-10-CM code for appendix disease is K38.9 (Disease of appendix, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on K38.9.
Within K38, choose K38.9 (Disease of appendix, unspecified) only when documentation doesn't support a more specific option: hyperplasia of appendix (K38.0), Appendicular concretions (K38.1), diverticulum of appendix (K38.2), fistula of appendix (K38.3) and other specified diseases of appendix (K38.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228) and DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific appendix disease codes (official index)
- specified NEC K38.8 — Other specified diseases of appendix
Common questions about appendix disease ICD-10 codes
What is the ICD-10 code for appendix disease?
- K38.9 — Disease of appendix, unspecified. More specific codes apply when the documentation supports them: K38.8.
Is K38.9 billable?
- Yes. K38.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K38.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K38.9 as a principal diagnosis.
Is K38.9 a CC or MCC?
- No. K38.9 is neither a CC nor an MCC under MS-DRG v44.0.