Diseases of appendix
ICD-10 Codes (2)
Updates & Changes
FY 2026 Updates
New Codes (1)
Revised Codes (2)
Deleted Codes
No codes deleted in this range for FY 2026
Historical Changes
- •FY 2025: Routine maintenance updates with minor terminology clarifications
- •FY 2024: Enhanced specificity requirements for certain code ranges
- •FY 2023: Updated documentation guidelines for improved clarity
Upcoming Changes
- •Proposed updates pending review by Coordination and Maintenance Committee
- •Under consideration: Enhanced digital health integration codes
Implementation Guidance
- •Review all FY 2026 updates for K35-K37 codes before implementation
- •Always verify the most current codes in the ICD-10-CM manual
- •Ensure clinical documentation supports the selected diagnosis codes
- +3 more guidance items...
Range Overview
The ICD-10 code range K35-K37 pertains to diseases of the appendix. This includes acute appendicitis, other appendicitis, and other diseases of the appendix. These codes are used to accurately document and categorize conditions related to the appendix for patient records, statistical analysis, and billing purposes.
Key Usage Points:
- •K35 codes are used for acute appendicitis, which includes conditions like appendicitis with generalized peritonitis and appendicitis with peritoneal abscess.
- •K36 codes represent other forms of appendicitis, such as chronic or recurrent appendicitis.
- •K37 codes are used for other diseases of the appendix, which could include conditions like appendiceal cysts or fibrosis of the appendix.
- •The fifth character in the code can be used to specify the presence of complications, such as peritonitis or abscess.
- •The sixth character can be used to denote whether the patient has a ruptured appendix.
Coding Guidelines
When to Use:
- ✓When a patient presents with symptoms of acute appendicitis, such as abdominal pain, nausea, and vomiting.
- ✓When a patient has a confirmed diagnosis of chronic or recurrent appendicitis.
- ✓When a patient has a disease of the appendix other than appendicitis, such as an appendiceal cyst.
- ✓When a patient has complications related to appendicitis, such as peritonitis or an abscess.
- ✓When a patient has a ruptured appendix.
When NOT to Use:
- ✗When a patient has symptoms of appendicitis but no confirmed diagnosis.
- ✗When a patient has an abdominal condition not related to the appendix.
- ✗When a patient has a history of appendicitis but no current disease.
- ✗When a patient has had an appendectomy but no current disease of the appendix.
- ✗When a patient has a disease of the digestive system not involving the appendix.
Code Exclusions
Always verify exclusions with the patient's clinical documentation and the ICD-10 coding guidelines.
Documentation Requirements
Documentation for diseases of the appendix should be comprehensive and include the type of appendicitis or other disease, the presence of any complications, and the status of the appendix (e.g., ruptured or not).
Clinical Information:
- •Type of appendicitis or other disease of the appendix
- •Presence of complications such as peritonitis or abscess
- •Status of the appendix (ruptured or not)
- •Results of any diagnostic tests or imaging
- •Treatment provided or planned
Supporting Evidence:
- •Clinical notes from the treating physician
- •Operative reports if surgery was performed
- •Pathology reports if applicable
- •Imaging reports if applicable
Good Documentation Example:
Patient presents with severe right lower quadrant pain, nausea, and vomiting. CT scan confirms acute appendicitis with peritoneal abscess. Plan is for immediate appendectomy.
Poor Documentation Example:
Patient has abdominal pain.
Common Documentation Errors:
- ⚠Not specifying the type of appendicitis or other disease of the appendix
- ⚠Not documenting the presence of complications
- ⚠Not indicating whether the appendix was ruptured
- ⚠Not including supporting evidence such as clinical notes or imaging reports
Range Statistics
Coding Complexity
Coding for diseases of the appendix can be moderately complex due to the need to accurately identify the specific condition, any complications, and the status of the appendix. Additionally, coders must navigate code exclusions and ensure comprehensive and accurate documentation.
Key Factors:
- ▸Determining the specific type of appendicitis or other disease of the appendix
- ▸Identifying and coding for any complications
- ▸Determining whether the appendix was ruptured
- ▸Navigating code exclusions
- ▸Ensuring comprehensive and accurate documentation
Specialty Focus
These codes are primarily used by general surgeons, emergency medicine physicians, and gastroenterologists.
Primary Specialties:
Clinical Scenarios:
- • A patient presents to the emergency department with severe right lower quadrant pain and is diagnosed with acute appendicitis.
- • A patient with a history of recurrent right lower quadrant pain is diagnosed with chronic appendicitis by a gastroenterologist.
- • A patient undergoes a CT scan for unrelated abdominal pain, and an appendiceal cyst is incidentally discovered.
- • A patient presents to the emergency department with generalized abdominal pain and fever, and is diagnosed with acute appendicitis with peritonitis.
- • A patient undergoes an appendectomy for acute appendicitis, and the pathology report reveals fibrosis of the appendix.
Resources & References
Resources for coding diseases of the appendix include the ICD-10 coding guidelines, clinical reference materials, and educational resources.
Official Guidelines:
- ICD-10-CM Official Guidelines for Coding and Reporting
- American Health Information Management Association (AHIMA) Coding Resources
- Centers for Disease Control and Prevention (CDC) ICD-10 Resources
Clinical References:
- American College of Surgeons Clinical Resources
- American Society of Gastrointestinal Endoscopy Clinical Guidelines
Educational Materials:
- American Academy of Professional Coders (AAPC) Educational Resources
- Medical Coding Academy Educational Resources
Frequently Asked Questions
How do I code for acute appendicitis with peritoneal abscess?
You would use code K35.3, Acute appendicitis with generalized peritonitis and gangrene, to represent acute appendicitis with peritoneal abscess.
Can I use a K35-K37 code for a patient with a history of appendicitis but no current disease?
No, the K35-K37 codes are for current diseases of the appendix. For a history of appendicitis, you would use a code from the Z86-Z87 range.