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K55.021 ICD-10-CM Code: Focal (segmental) acute infarction of small intestine

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 393 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH MCC (MDC 06)
  • MS-DRG 394 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH CC (MDC 06)
  • MS-DRG 395 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITHOUT CC/MCC (MDC 06)
  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Focal (segmental) acute infarction of small intestine is a billable ICD-10-CM diagnosis code (K55.021).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for K55.021 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Infarct, infarction, intestine (acute) (agnogenic) (embolic) (hemorrhagic) (nonocclusive) (nonthrombotic) (occlusive) (thrombotic) (with gangrene), small, focal

Frequently Compared Codes

The official Excludes notes on K55.021 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2017 — 2016-10-01
    Added to the code set
    Focal (segmental) acute infarction of small intestine
    FY2017 changes

Verify Before Coding

  • MCC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Relationships & Classification

Other codes that name K55.021 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

2 Excludes2 notes: I74 (via K55.0.-), I82 (via K55.0.-).

Potential MS-DRG Relationships (FY2026)

MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 23 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 5 MS-DRGs: DRG 393 (MDC 06), DRG 394 (MDC 06), DRG 395 (MDC 06), DRG 791 (MDC 15), DRG 793 (MDC 15).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):DIG025 — Other specified and unspecified gastrointestinal disorders (default); CIR026 — Peripheral and visceral vascular disease.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as MCC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

K52.89 — Other specified noninfective gastroenteritis and colitis, K52.9 — Noninfective gastroenteritis and colitis, unspecified, K55.011 — Focal (segmental) acute (reversible) ischemia of small intestine, K55.012 — Diffuse acute (reversible) ischemia of small intestine, K55.019 — Acute (reversible) ischemia of small intestine, extent unspecified, K55.022 — Diffuse acute infarction of small intestine, K55.029 — Acute infarction of small intestine, extent unspecified, K55.031 — Focal (segmental) acute (reversible) ischemia of large intestine, K55.032 — Diffuse acute (reversible) ischemia of large intestine, K55.039 — Acute (reversible) ischemia of large intestine, extent unspecified, +215 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Other specified and unspecified gastrointestinal disorders, Peripheral and visceral vascular disease).

I73.9 — Peripheral vascular disease, unspecified, K55.0 — Acute vascular disorders of intestine, K55.011 — Focal (segmental) acute (reversible) ischemia of small intestine, K55.012 — Diffuse acute (reversible) ischemia of small intestine, K55.019 — Acute (reversible) ischemia of small intestine, extent unspecified, K55.022 — Diffuse acute infarction of small intestine, K55.029 — Acute infarction of small intestine, extent unspecified, K55.031 — Focal (segmental) acute (reversible) ischemia of large intestine, K55.032 — Diffuse acute (reversible) ischemia of large intestine, K55.039 — Acute (reversible) ischemia of large intestine, extent unspecified, +328 more

Lab tests where this diagnosis supports Medicare coverage

Medicare's National Coverage Determinations list this diagnosis as medical justification for these lab tests.

Fecal Occult Blood Test (FOBT) (lab test), Gamma-glutamyl Transferase (GGT) Test (lab test), Iron Panel (lab test), Partial Thromboplastin Time (PTT) Test (lab test), Prothrombin Time Test and INR (PT/INR) (lab test)

Contextual Map

Every relationship of K55.021 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • K00-K95 — Chapter 11: Diseases of the Digestive System (K00-K95) (K00-K95) [Hierarchy]
  • K55-K64 — Other diseases of intestines [Hierarchy]

Referenced by Excludes2 notes

  • I74 — Arterial embolism and thrombosis [Excludes2](via K55.0.-): “mesenteric embolism and thrombosis (K55.0-)” · check together
  • I82 — Other venous embolism and thrombosis [Excludes2](via K55.0.-): “mesenteric (K55.0-)” · check together

Clinical classification (CCSR)

  • DIG025 — Other specified and unspecified gastrointestinal disorders [CCSR]
  • CIR026 — Peripheral and visceral vascular disease [CCSR]

Potential MS-DRG

  • MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”
  • DRG 393 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH MCC [MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITH MCC (MDC 06)”
  • DRG 394 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITH CC [MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITH CC (MDC 06)”
  • DRG 395 — OTHER DIGESTIVE SYSTEM DIAGNOSES WITHOUT CC/MCC [MS-DRG]: “OTHER DIGESTIVE SYSTEM DIAGNOSES WITHOUT CC/MCC (MDC 06)”
  • DRG 791 — PREMATURITY WITH MAJOR PROBLEMS [MS-DRG]: “PREMATURITY WITH MAJOR PROBLEMS (MDC 15)”
  • DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS [MS-DRG]: “FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)”

MDC crossing · procedures (5744)

  • MDC 06 — Diseases and Disorders of the Digestive System [MDC crossing]: “Diseases and Disorders of the Digestive System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period [MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • 008Q0ZZ — Division of Vagus Nerve, Open Approach [Same-MDC procedure]: “Division of Vagus Nerve, Open Approach — grouped in MDC 06, the procedure side of this code's crossing.” · check together
  • 008Q3ZZ — Division of Vagus Nerve, Percutaneous Approach [Same-MDC procedure]: “Division of Vagus Nerve, Percutaneous Approach — grouped in MDC 06, the procedure side of this code's crossing.” · check together
  • 008Q4ZZ — Division of Vagus Nerve, Percutaneous Endoscopic Approach [Same-MDC procedure]: “Division of Vagus Nerve, Percutaneous Endoscopic Approach — grouped in MDC 06, the procedure side of this code's crossing.” · check together
  • 02BP3ZZ — Excision of Pulmonary Trunk, Percutaneous Approach [Same-MDC procedure]: “Excision of Pulmonary Trunk, Percutaneous Approach — grouped in MDC 06, the procedure side of this code's crossing.” · check together
  • 02BQ3ZZ — Excision of Right Pulmonary Artery, Percutaneous Approach [Same-MDC procedure]: “Excision of Right Pulmonary Artery, Percutaneous Approach — grouped in MDC 06, the procedure side of this code's crossing.” · check together
  • and 5739 more

Index entries

  • Infarct, infarction, intestine (acute) (agnogenic) (embolic) (hemorrhagic) (nonocclusive) (nonthrombotic) (occlusive) (thrombotic) (with gangrene), small, focal[Index term]

Nearest codes (36)

  • K55 — Vascular disorders of intestine [Sibling]
  • K55.0 — Acute vascular disorders of intestine [Sibling]
  • K55.01 — Acute (reversible) ischemia of small intestine [Sibling]
  • K55.011 — Focal (segmental) acute (reversible) ischemia of small intestine [Sibling]
  • K55.012 — Diffuse acute (reversible) ischemia of small intestine [Sibling]
  • K55.019 — Acute (reversible) ischemia of small intestine, extent unspecified [Sibling]
  • K55.02 — Acute infarction of small intestine [Sibling]
  • K55.022 — Diffuse acute infarction of small intestine [Sibling]
  • and 28 more

Change history

  • FY2017 — Added to the code set [Change history]

Nearest Codes in This Family

Official ICD-10-CM classifications closest to K55.021 in its code family, with their registry titles.

  • K55.01 — Acute (reversible) ischemia of small intestine
  • K55.011 — Focal (segmental) acute (reversible) ischemia of small intestine
  • K55.012 — Diffuse acute (reversible) ischemia of small intestine
  • K55.019 — Acute (reversible) ischemia of small intestine, extent unspecified
  • K55.02 — Acute infarction of small intestine
  • K55.022 — Diffuse acute infarction of small intestine
  • K55.029 — Acute infarction of small intestine, extent unspecified
  • K55.03 — Acute (reversible) ischemia of large intestine
  • K55.031 — Focal (segmental) acute (reversible) ischemia of large intestine
  • K55.032 — Diffuse acute (reversible) ischemia of large intestine

View all codes in the K55 family