K35.21 – Acute appendicitis with generalized peritonitis, with abscess
ICD-10-CM 2027 diagnosis code · Diseases of appendix
ICD-10-CM code
K35.21
- Code
K35.21(claims format:K3521)- Description
- Acute appendicitis with generalized peritonitis, with abscess
- Short description
- Acute appendicitis with gen peritonitis, with abscess
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 11. Diseases of the digestive system (K00-K95)
- Block
- K35-K38 Diseases of appendix
- Parent codes
- K35 › K35.2
Billable codes under K35.21
K35.21 is a header code and cannot be used on claims. Choose the most specific code:
- K35.210 – Acute appendicitis with generalized peritonitis, without perforation, with abscessBillable
- K35.211 – Acute appendicitis with generalized peritonitis, with perforation and abscessBillable
- K35.219 – Acute appendicitis with generalized peritonitis, with abscess, unspecified as to perforationBillable
Related codes in K35.2
Frequently asked questions
What is ICD-10 code K35.21?
K35.21 is the ICD-10-CM code for acute appendicitis with generalized peritonitis, with abscess, in the block K35-K38 (Diseases of appendix).
Is K35.21 a billable code?
No. K35.21 is a header code with more specific child codes; report one of the billable codes listed above.
What category does K35.21 belong to?
It belongs to category K35 – Acute appendicitis.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.