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ICD-10-CM 2027 diagnosis code

K37Unspecified appendicitis

✓ Billable / specific

K37 is a valid, billable ICD-10-CM code for unspecified appendicitis. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Appendicitis, ICD-10 code for Perityphlitis.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About K37

K37 is the ICD-10-CM diagnosis code for unspecified appendicitis. It belongs to block K35-K38 (diseases of appendix) and chapter 11 (diseases of the digestive system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 541 (appendicitis, unqualified).

Coding notes

Excludes1Not coded here — never report together with this code

Notes that apply from higher levels

Instructions written at a parent level also apply to K37.

Broader instructions also apply from Chapter 11: Diseases of the digestive system.

Alphabetic index entries

2 entries

Terms in the official ICD-10-CM index that lead to K37.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 541Appendicitis, unqualifiedexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about K37

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.

What DRG does K37 group to?

K37 is used in the MS-DRG v44.0 logic for MS-DRG 393 (Other Digestive System Diagnoses with MCC), MS-DRG 394 (Other Digestive System Diagnoses with CC) and MS-DRG 395 (Other Digestive System Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for K37?

The CMS General Equivalence Mappings map K37 to ICD-9-CM 541.