What is ICD-10 code K27.1?

K27.1 is the ICD-10-CM diagnosis code for Acute peptic ulcer, site unspecified, with perforation. A sudden peptic ulcer at an unspecified location that has perforated, creating a hole through the wall. It belongs to the ICD-10-CM chapter for diseases of the digestive system (k00-k95). K27.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. K27.1 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. K27.1 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. K27.1 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.

Which HCC does K27.1 map to under V28?

K27.1 maps to CMS-HCC V28 78 (Intestinal Obstruction/Perforation). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does K27.1 pay in RAF?

K27.1 carries a community, non-dual, aged (CNA) RAF weight of 0.326 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for K27.1?

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 K27.1, V28 maps to Intestinal Obstruction/Perforation at RAF 0.326 while V24 mapped to Intestinal Obstruction/Perforation at RAF 0.219. Both models can still appear in legacy data and in payer-specific lookback periods.

2026 ICD-10-CM K27.1: Acute peptic ulcer, site

K27.1 maps to CMS-HCC V28 78 (RAF 0.326). Documentation must support MEAT. MEAT criteria · RAF calculator · free HCC coding tools

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Code lookupK27.1Effective 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)

K27.1

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

Acute peptic ulcer, site unspecified, with perforation

A sudden peptic ulcer at an unspecified location that has perforated, creating a hole through the wall.

Buddy Insight

CMS-HCC V28

Mapped

HCC 78

Intestinal Obstruction/Perfor...

RAF 0.326

CMS-HCC V24

Mapped

HCC 33

Intestinal Obstruction/Perfor...

RAF 0.219

ACA/HHS

Mapped

HCC 42

HHS-HCC 42

Varies by metal level

ESRD/PACE

Mapped

HCC 33

Intestinal Obstruction/Perfor...

RAF 0.078

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

K27Peptic ulcer, site unspecified

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

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for K27.1 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for K27.1 in this effective period.

Related Child Codes

Official

K27.0Acute peptic ulcer, site unspecified, with hemorrhage

K27.2Acute peptic ulcer, site unspecified, with both hemorrhage and perforation

K27.3Acute peptic ulcer, site unspecified, without hemorrhage or perforation

K27.4Chronic or unspecified peptic ulcer, site unspecified, with hemorrhage

K27.5Chronic or unspecified peptic ulcer, site unspecified, with perforation

Includes

Official

gastroduodenal ulcer NOS
peptic ulcer NOS

Excludes 1

Official

peptic ulcer of newborn (P78.82)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for K27.1 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 K27.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of acute peptic ulcer with perforation

Evidence of perforation (free air on imaging, peritoneal signs, or operative findings)

Acuity confirmed as acute

Documentation that the specific ulcer site was NOT identified or is truly unknown

MEAT Support

HCC Buddy guidance

Provider documentation of acute peptic ulcer with perforation

Evidence of perforation (free air on imaging, peritoneal signs, or operative findings)

Acuity confirmed as acute

Documentation that the specific ulcer site was NOT identified or is truly unknown

Audit Caution

HCC Buddy guidance

Using this unspecified-site code when the anatomic location IS documented — always use the most specific site code available

Failing to query the provider about the ulcer site, especially when operative or endoscopic reports are available

Not capturing concurrent hemorrhage when present (would require K27.2)

Confusing acute vs. chronic acuity which changes the code to K27.5

Common Mistakes

HCC Buddy guidance

K25.1 — Acute gastric ulcer with perforation: use when the gastric site is documented

K26.1 — Acute duodenal ulcer with perforation: use when the duodenal site is documented

K28.1 — Acute gastrojejunal ulcer with perforation: use when gastrojejunal site is documented

K27.2 — Acute peptic ulcer, site unspecified, with both hemorrhage and perforation: when bleeding is also present

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is K27.1 an HCC code?

Yes. K27.1 (Acute peptic ulcer, site unspecified, with perforation) maps to Intestinal Obstruction/Perforation under the CMS-HCC V28 risk adjustment model (and Intestinal Obstruction/Perforation under V24), with a community non-dual aged RAF of 0.326. It is billable for payment year 2026.

Coder answer: K27.1 is billable and maps to V28 HCC 78, Intestinal Obstruction/Perforation. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: K27.1
Description: Acute peptic ulcer, site unspecified, with perforation
HCC (V28): HCC 78 — Intestinal Obstruction/Perforation
RAF: 0.326
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 78, Intestinal Obstruction/Perforation

0.326

V24HCC 33, Intestinal Obstruction/Perforation

0.219

ESRDHCC 33, Intestinal Obstruction/Perforation

0.078

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work K27.1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for K27.1

For K27.1 to 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 K27.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

K27.1 is the ICD-10-CM diagnosis code for acute peptic ulcer, site unspecified, with perforation. A sudden peptic ulcer at an unspecified location that has perforated, creating a hole through the wall. K27.1 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, K27.1 maps to Intestinal Obstruction/Perforation (HCC 78) with a community, non-dual, aged base RAF weight of 0.326. Under the older V24 model, K27.1 mapped to the same category but with a base RAF weight of 0.219, 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 often requiring surgical intervention; ensure this is documented. Because K27.1 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 K27.1 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 often requiring surgical intervention; ensure this is documented
•Verify the site is truly unspecified; if known, use more specific K25 or K26 codes

Clinical Significance

Acute peptic ulcer of unspecified site with perforation is used when an acute ulcer perforates but the specific anatomic location (gastric, duodenal, or gastrojejunal) cannot be determined from the documentation. Perforation of any peptic ulcer site is a surgical emergency requiring urgent intervention. This code should prompt a query for site specification whenever possible.

Documentation Requirements

✓Provider documentation of acute peptic ulcer with perforation
✓Evidence of perforation (free air on imaging, peritoneal signs, or operative findings)
✓Acuity confirmed as acute
✓Documentation that the specific ulcer site was NOT identified or is truly unknown
✓Surgical findings and intervention details

Commonly Confused Codes

•K25.1: Acute gastric ulcer with perforation: use when the gastric site is documented
•K26.1: Acute duodenal ulcer with perforation: use when the duodenal site is documented
•K28.1: Acute gastrojejunal ulcer with perforation: use when gastrojejunal site is documented
•K27.2: Acute peptic ulcer, site unspecified, with both hemorrhage and perforation: when bleeding is also present
•K27.5: Chronic or unspecified peptic ulcer, site unspecified, with perforation: chronic or unspecified acuity