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ICD-10-CM 2027 diagnosis code

K27.1Acute peptic ulcer, site unspecified, with perforation

✓ Billable / specificMCC — major complication/comorbidity

K27.1 is a valid, billable ICD-10-CM code for acute peptic ulcer, site unspecified, with perforation. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

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 K27.1

K27.1 is the ICD-10-CM diagnosis code for acute peptic ulcer, site unspecified, with perforation. It belongs to category K27 (peptic ulcer, site unspecified), block K20-K31 (diseases of esophagus, stomach and duodenum) 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.

Within K27, choose K27.1 (Acute peptic ulcer, site unspecified, with perforation) only when documentation doesn't support a more specific option: acute peptic ulcer, site unspecified, with hemorrhage (K27.0), acute peptic ulcer, site unspecified, with both hemorrhage and perforation (K27.2), acute peptic ulcer, site unspecified, without hemorrhage or perforation (K27.3), chronic or unspecified peptic ulcer, site unspecified, with hemorrhage (K27.4), chronic or unspecified peptic ulcer, site unspecified, with perforation (K27.5), chronic or unspecified peptic ulcer, site unspecified, with both hemorrhage and perforation (K27.6), chronic peptic ulcer, site unspecified, without hemorrhage or perforation (K27.7) and unspecified as acute or chronic, without hemorrhage or perforation (K27.9).

Use an additional code to identify: alcohol abuse and dependence (F10.-).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 380 (Complicated Peptic Ulcer with MCC, relative weight 1.9245), DRG 381 (Complicated Peptic Ulcer with CC, relative weight 1.0838) and DRG 382 (Complicated Peptic Ulcer without CC/MCC, relative weight 0.7281), 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 533.10 (acute peptic ulcer of unspecified site with perforation, without mention of obstruction).

Notes that apply from higher levels

Instructions written at a parent level also apply to K27.1.

› From K27 Peptic ulcer, site unspecified
Includes
  • gastroduodenal ulcer NOS
  • peptic ulcer NOS
Excludes1
  • peptic ulcer of newborn (P78.82)
Use additional code
  • code to identify:
  • alcohol abuse and dependence (F10.-)

Broader instructions also apply from K20-K31 Diseases of esophagus, stomach and duodenum and Chapter 11: Diseases of the digestive system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to K27.1.

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 →
  • 533.10Acute peptic ulcer of unspecified site with perforation, without mention of obstructionapproximate

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 K27.1

Is K27.1 billable?

Yes. K27.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can K27.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict K27.1 as a principal diagnosis.

Is K27.1 a CC or MCC?

K27.1 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does K27.1 group to?

K27.1 is used in the MS-DRG v44.0 logic for MS-DRG 380 (Complicated Peptic Ulcer with MCC), MS-DRG 381 (Complicated Peptic Ulcer with CC) and MS-DRG 382 (Complicated Peptic Ulcer 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 K27.1?

The CMS General Equivalence Mappings map K27.1 to ICD-9-CM 533.10.