What is ICD-10 code K28.1?

K28.1 is the ICD-10-CM diagnosis code for Acute gastrojejunal ulcer with perforation. A sudden gastrojejunal ulcer with a hole or rupture in the stomach or intestinal wall. It belongs to the ICD-10-CM chapter for diseases of the digestive system (k00-k95). K28.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. K28.1 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. K28.1 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. K28.1 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for K28.1?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For K28.1, V28 maps to Intestinal Obstruction/Perforation at RAF 0.000 while V24 mapped to Intestinal Obstruction/Perforation at RAF 0.226. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting K28.1?

Perforation is a serious complication requiring urgent intervention; confirm perforation is documented before coding Do not use this code if hemorrhage is also present; use K28.2 instead Because K28.1 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

K28.1 ICD-10 Code: Acute gastrojejunal ulcer

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupK28.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the digestive system (K00-K95) / Diseases of esophagus, stomach and duodenum (K20-K31)

K28.1

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Acute gastrojejunal ulcer with perforation

A sudden gastrojejunal ulcer with a hole or rupture in the stomach or intestinal wall.

Buddy Insight

Acute gastrojejunal ulcer with perforation is a surgical emergency occurring at the gastrojejunal anastomosis, typically as a complication of prior gastric surgery (e.

CMS-HCC V28

Mapped

HCC 78

Intestinal Obstruction/Perfor...

RAF 0.0

CMS-HCC V24

Mapped

HCC 33

Intestinal Obstruction/Perfor...

RAF 0.226

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 33

Intestinal Obstruction/Perfor...

RAF 0.0

RXHCC

Not risk-adjusted for this model/period.

RAF 0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

K28Gastrojejunal ulcer

K28.1Acute gastrojejunal ulcer with perforation

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for K28.1 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for K28.1 in this effective period.

Related Child Codes

Official

K28.0Acute gastrojejunal ulcer with hemorrhage

K28.2Acute gastrojejunal ulcer with both hemorrhage and perforation

K28.3Acute gastrojejunal ulcer without hemorrhage or perforation

K28.4Chronic or unspecified gastrojejunal ulcer with hemorrhage

K28.5Chronic or unspecified gastrojejunal ulcer with perforation

Includes

Official

anastomotic ulcer (peptic) or erosion
gastrocolic ulcer (peptic) or erosion
gastrointestinal ulcer (peptic) or erosion
gastrojejunal ulcer (peptic) or erosion
jejunal ulcer (peptic) or erosion

Excludes 1

Official

primary ulcer of small intestine (K63.3)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for K28.1 in this effective period.

Use Additional

Official

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

Code Also

Official

ICD-10-CM does not list Code Also instructions for K28.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of acute gastrojejunal (marginal/stomal) ulcer with perforation

Surgical history confirming prior gastric surgery with gastrojejunal anastomosis

Evidence of perforation at the anastomotic site

Acuity confirmed as acute

MEAT Support

HCC Buddy guidance

Provider documentation of acute gastrojejunal (marginal/stomal) ulcer with perforation

Surgical history confirming prior gastric surgery with gastrojejunal anastomosis

Evidence of perforation at the anastomotic site

Acuity confirmed as acute

Audit Caution

HCC Buddy guidance

Confusing gastrojejunal (marginal) ulcers with native gastric ulcers — the K28 category is specifically for post-surgical anastomotic ulcers

Not documenting the surgical history that identifies this as a gastrojejunal ulcer

Missing concurrent hemorrhage that would change the code to K28.2

Using K25 (gastric) codes for ulcers at a gastrojejunal anastomosis

Common Mistakes

HCC Buddy guidance

K28.0 — Acute gastrojejunal ulcer with hemorrhage: bleeding only, no perforation

K28.2 — Acute gastrojejunal ulcer with both hemorrhage and perforation: use when both present

K28.5 — Chronic or unspecified gastrojejunal ulcer with perforation: chronic or unspecified acuity

K25.1 — Acute gastric ulcer with perforation: native stomach ulcer, not at anastomotic site

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is K28.1 an HCC code?

Yes. K28.1 maps to Intestinal Obstruction/Perforation under the CMS-HCC V28 risk adjustment model (and Intestinal Obstruction/Perforation under V24).

HCC Category Mapping

V28HCC 78, Intestinal Obstruction/Perforation

0.000

V24HCC 33, Intestinal Obstruction/Perforation

0.226

ESRDHCC 33, Intestinal Obstruction/Perforation

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for K28.1

For K28.1to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed K28.1 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

K28.1 is the ICD-10-CM diagnosis code for acute gastrojejunal ulcer with perforation. A sudden gastrojejunal ulcer with a hole or rupture in the stomach or intestinal wall. K28.1 sits in the ICD-10-CM chapter for diseases of the digestive system (k00-k95), within the section covering diseases of esophagus, stomach and duodenum (k20-k31).

Under the CMS-HCC V28 risk adjustment model, K28.1 maps to Intestinal Obstruction/Perforation (HCC 78) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, K28.1 mapped to the same category but with a base RAF weight of 0.226, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Perforation is a serious complication requiring urgent intervention; confirm perforation is documented before coding. Because K28.1 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for K28.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Perforation is a serious complication requiring urgent intervention; confirm perforation is documented before coding
•Do not use this code if hemorrhage is also present; use K28.2 instead

Clinical Significance

Acute gastrojejunal ulcer with perforation is a surgical emergency occurring at the gastrojejunal anastomosis, typically as a complication of prior gastric surgery (e.g., Billroth procedures or gastric bypass). The perforation at this surgical site carries unique risks including anastomotic leak and peritonitis. This code specifically identifies the marginal ulcer complication in post-surgical patients.

Documentation Requirements

✓Provider documentation of acute gastrojejunal (marginal/stomal) ulcer with perforation
✓Surgical history confirming prior gastric surgery with gastrojejunal anastomosis
✓Evidence of perforation at the anastomotic site
✓Acuity confirmed as acute
✓Operative findings and surgical repair documentation

Commonly Confused Codes

•K28.0: Acute gastrojejunal ulcer with hemorrhage: bleeding only, no perforation
•K28.2: Acute gastrojejunal ulcer with both hemorrhage and perforation: use when both present
•K28.5: Chronic or unspecified gastrojejunal ulcer with perforation: chronic or unspecified acuity
•K25.1: Acute gastric ulcer with perforation: native stomach ulcer, not at anastomotic site
•K91.1: Postgastric surgery syndromes: a broader post-surgical category, not specific to ulcer perforation