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v1.0.0
ICD-10 Guide
DiagnosesAppendectomy

Appendectomy

ICD-10 Coding for Appendectomy(K35.2, K38.9)

PRIMARY SPECIALTYGeneral Surgery
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Appendectomy?
Essential facts and insights about Appendectomy

Key Clinical Considerations:

  • Acute abdominal pain, typically in the right lower quadrant.
  • Elevated white blood cell count indicating possible infection.
  • Physical examination may reveal tenderness in the right lower quadrant, rebound tenderness, or guarding.
  • Imaging studies such as ultrasound or CT scan may show an enlarged or inflamed appendix.
  • Severity criteria include the presence of perforation or abscess formation.

Clinical Information

Clinical Criteria & Documentation Requirements

  • Complete medical history and physical examination findings must be documented.
  • Specific terminology such as 'acute appendicitis' or 'appendiceal abscess' should be used.
  • Examples include documenting the patient's symptoms, lab results, and imaging findings.
  • Medical necessity must be established through documentation of symptoms and treatment rationale.
  • Quality measures may include documentation of pre-operative assessments and post-operative outcomes.

Coding Guidelines

Usage Guidelines & Examples

  • Use K35.2 for acute appendicitis with localized peritonitis; use K38.9 for unspecified abdominal pain.
  • Do not use K35.2 if the patient has a history of appendectomy or if the diagnosis is not confirmed.
  • K35.0 (acute appendicitis with generalized peritonitis) is similar but indicates a more severe condition.
  • Common errors include using the wrong code for chronic appendicitis or failing to document the acute nature of the condition.
  • In complex cases, ensure all symptoms and findings are documented to support the selected code.

Code Exclusions

Important Exclusions

  • Excludes conditions such as chronic appendicitis or appendiceal tumors.
  • Alternative codes for excluded conditions include K35.3 for chronic appendicitis.
  • Conditions are excluded due to differing treatment protocols and clinical implications.
  • Common mistakes include misclassifying chronic conditions as acute appendicitis.
  • Related but distinct conditions include gastrointestinal obstruction and inflammatory bowel disease.

Related ICD-10 Codes

Primary Codes
K35.2
Acute appendicitis with localized peritonitis
K38.9
Unspecified abdominal pain
Ancillary Codes
R10.31
Differential Codes
K35.80

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

General Surgery

Specialty Applications

  • Applies to patients presenting with symptoms of appendicitis.
  • Patient populations include all ages, but most common in adolescents and young adults.
  • Clinical settings include inpatient surgical units and emergency departments.
  • General surgery is the primary specialty involved in appendectomy procedures.
  • Used in treatment contexts where surgical intervention is necessary for appendicitis.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Template 1

Template: 'Patient diagnosed with acute appendicitis based on clinical findings of right lower quadrant pain and elevated WBC.'

Template 2

Template: 'Clinical presentation consistent with appendicitis including fever and nausea.'

Template 3

Template: 'Diagnostic criteria for appendicitis met as evidenced by CT scan showing an inflamed appendix.'

Template 4

Template: 'Treatment plan initiated for appendicitis with laparoscopic appendectomy scheduled.'

Template 5

Template: 'Follow-up care for appendicitis including monitoring for infection and pain management.'

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What documentation is required for this diagnosis?

Documentation must include clinical findings, lab results, and imaging studies supporting the diagnosis of appendicitis.

How does this differ from similar diagnoses?

Acute appendicitis is characterized by specific symptoms and findings that differentiate it from other abdominal conditions.

What are common billing considerations?

Ensure that the diagnosis is clearly documented to support the medical necessity for surgery and avoid claim denials.

What procedures are typically associated?

CPT codes for appendectomy procedures include 44950 (appendectomy, open) and 44960 (appendectomy, laparoscopic).

Are there any quality reporting implications?

Quality measures may include tracking post-operative complications and adherence to surgical protocols.