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Modifier Coding Alert


Have No Fear with Future Appendicitis Codes

The ‘other’ appendicitis codes are expanded and more precise.

If coding appendicitis is commonplace for you and you’ve been worried about big changes with ICD-10, you can stop worrying. The update is minor, just more detailed.

The transition to ICD-10 is less than a year away so review this glimpse of the new codes to ensure you’re ready.

Dig into the Note as Usual

When coding acute appendicitis with ICD-9, you need to rely on your physician’s note to look for localized or generalized peritonitis when determining which of the following five codes to use:

  • 540.0 — Acute appendicitis with generalized peritonitis
  • 540.1 — Acute appendicitis with peritoneal abscess
  • 540.9 — Acute appendicitis without peritonitis
  • 541 — Appendicitis unqualified
  • 542 — Other appendicitis.

Being More Specific is the Future

Coding with ICD-10 will be similar to coding with ICD-9. You still have to start your decision-making by looking for the presence or absence of peritonitis within the documentation of the service. You’ll need this information because you’ll find that the ICD-10 codes are more specific. Therefore, your coding will be more accurate and in-line with the specification in the documentation. You’ll choose from the following codes: 

  • K35.2 — Acute appendicitis with generalized peritonitis
  • K35.3 — Acute appendicitis with localized peritonitis
  • K35.80 — Unspecified acute appendicitis
  • K35.89 — Other acute appendicitis
  • K36 — Other appendicitis
  • K37 — Unspecified appendicitis
  • K38.0 — Hyperplasia of appendix
  • K38.1 — Appendicular concretions
  • K38.2 — Diverticulum of appendix
  • K38.3 — Fistula of appendix
  • K38.8 — Other specified diseases of appendix
  • K38.9 — Disease of appendix, unspecified.

Watch out: Other and unspecified acute appendicitis expands further to cover two individual codes. One that includes acute appendicitis without any peritonitis (K35.89) and acute appendicitis that is not otherwise specified (NOS) (K35.80).

Note: Use K35.3 to report acute appendicitis with peritoneal abscess. ICD-9 currently uses 540.1.

Example: An 18-year-old male patient reports to your office with complaints of severe epigastric pain that has been present for the past 48 hours with increasing intensity. He also complains of nausea and vomiting.

Your physician conducts a comprehensive evaluation of the patient during which he observes tenderness to percussion and Dunphy’s sign (increased pain with coughing) positive. He suspects acute appendicitis and orders a complete blood count (CBC), a test for C-reactive protein, and urinalysis. He also asks for a CT scan. Based on the findings at examination and tests, your gastroenterologist arrives at a diagnosis of appendicitis with localized peritonitis. Once ICD-10 is in effect, you’ll report the diagnosis with K35.3.

Be Heard to Avoid Another Delay

Physician groups have sent requests to Congress to delay the implementation of ICD-10 until 2017. To see what these groups are asking Congress, visit and search on ICD-10.

According to CMS, the healthcare industry lost approximately 6.8 billion dollars as a result of the last delay. Losses included investments and missed opportunities for better health data to improve quality of care and patient safety.

Be proactive: If you don’t want to see another delay, contact your public officials and ask them to support the Oct. 1, 2015 compliance date and to vote “no” on any additional delays. You can contact your legislators using American Health Information Management Association’s (AHIMA) advocacy tools by visiting

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