ICD-10-CM 2027
ICD-10 code for Perityphlitis
From the official ICD-10-CM alphabetic index entry “Perityphlitis”. Page updated September 29, 2026.
About coding Perityphlitis
The ICD-10-CM code for Perityphlitis is K37 (Unspecified appendicitis).
Don't report K37 together with the conditions in its Excludes1 note: unspecified appendicitis with peritonitis (K35.2-, K35.3-).
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.
Don't confuse with (Excludes1 for K37)
Common questions about Perityphlitis ICD-10 codes
What is the ICD-10 code for Perityphlitis?
- K37 — Unspecified appendicitis.
Is K37 billable?
- Yes. K37 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K37 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K37 as a principal diagnosis.
Is K37 a CC or MCC?
- No. K37 is neither a CC nor an MCC under MS-DRG v44.0.