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I81 ICD-10-CM Code: Portal vein thrombosis

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

Coding at a Glance

Tabular directives
1 inclusion term · 2 Excludes2

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 441 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITH MCC (MDC 07)
  • MS-DRG 442 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITH CC (MDC 07)
  • MS-DRG 443 — DISORDERS OF LIVER EXCEPT MALIGNANCY, CIRRHOSIS OR ALCOHOLIC HEPATITIS WITHOUT CC/MCC (MDC 07)

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.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I81 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Portal (vein) obstruction

Excludes2 — Not Included Here

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

Coder workflow for I81

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

  • Excludes2 — not part of I81(2 notes)

    Coding workflow: The conditions named in this note are not included in I81. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareI82.0, K75.1

    See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse I81 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of I81 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • I82.0— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of hepatic vein thrombosis adds I82.0; it is not part of this code and both may be reported when both are documented.

    Full comparison: I81 vs I82.0 →

  • K75.1— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of phlebitis of portal vein adds K75.1; it is not part of this code and both may be reported when both are documented.

    Full comparison: I81 vs K75.1 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Code Overview

Portal vein thrombosis is a billable ICD-10-CM diagnosis code (I81).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (6)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • MCC as a secondary diagnosis (FY2027). 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 in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name I81 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.

Referenced by 2 Excludes2 notes across 2 chapters: I82 — Other venous embolism and thrombosis, K76 — Other diseases of liver.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: 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 202 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 441 (MDC 07), DRG 442 (MDC 07), DRG 443 (MDC 07).

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

Clinical classification (AHRQ CCSR):CIR033 — Acute phlebitis; thrombophlebitis and thromboembolism (default).

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.

E13.628 — Other specified diabetes mellitus with other skin complications, E13.630 — Other specified diabetes mellitus with periodontal disease, E13.638 — Other specified diabetes mellitus with other oral complications, E13.649 — Other specified diabetes mellitus with hypoglycemia without coma, E13.65 — Other specified diabetes mellitus with hyperglycemia, E13.69 — Other specified diabetes mellitus with other specified complication, E13.8 — Other specified diabetes mellitus with unspecified complications, I27.841 — Fontan-associated lymphatic dysfunction, I27.848 — Other Fontan-associated condition, I27.849 — Fontan related circulation, unspecified, I82.210 — Acute embolism and thrombosis of superior vena cava, I82.211 — Chronic embolism and thrombosis of superior vena cava, I82.290 — Acute embolism and thrombosis of other thoracic veins, I82.291 — Chronic embolism and thrombosis of other thoracic veins, I82.401 — Acute embolism and thrombosis of unspecified deep veins of right lower extremity, I82.402 — Acute embolism and thrombosis of unspecified deep veins of left lower extremity, I82.403 — Acute embolism and thrombosis of unspecified deep veins of lower extremity, bilateral, I82.409 — Acute embolism and thrombosis of unspecified deep veins of unspecified lower extremity, I82.411 — Acute embolism and thrombosis of right femoral vein, I82.412 — Acute embolism and thrombosis of left femoral vein, +181 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Acute phlebitis; thrombophlebitis and thromboembolism).

I80.252 — Phlebitis and thrombophlebitis of left calf muscular vein, I80.253 — Phlebitis and thrombophlebitis of calf muscular vein, bilateral, I80.259 — Phlebitis and thrombophlebitis of unspecified calf muscular vein, I80.291 — Phlebitis and thrombophlebitis of other deep vessels of right lower extremity, I80.292 — Phlebitis and thrombophlebitis of other deep vessels of left lower extremity, I80.293 — Phlebitis and thrombophlebitis of other deep vessels of lower extremity, bilateral, I80.299 — Phlebitis and thrombophlebitis of other deep vessels of unspecified lower extremity, I80.3 — Phlebitis and thrombophlebitis of lower extremities, unspecified, I80.8 — Phlebitis and thrombophlebitis of other sites, I80.9 — Phlebitis and thrombophlebitis of unspecified site, I82.0 — Budd-Chiari syndrome, I82.1 — Thrombophlebitis migrans, I82.210 — Acute embolism and thrombosis of superior vena cava, I82.220 — Acute embolism and thrombosis of inferior vena cava, I82.290 — Acute embolism and thrombosis of other thoracic veins, I82.3 — Embolism and thrombosis of renal vein, I82.401 — Acute embolism and thrombosis of unspecified deep veins of right lower extremity, I82.402 — Acute embolism and thrombosis of unspecified deep veins of left lower extremity, I82.403 — Acute embolism and thrombosis of unspecified deep veins of lower extremity, bilateral, I82.409 — Acute embolism and thrombosis of unspecified deep veins of unspecified lower extremity, +106 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Embolism”, “Thrombosis, thrombotic”, “Obstruction, obstructed, obstructive”; these codes share that main term but sit in a different category of the Tabular List.

I74.11 — Embolism and thrombosis of thoracic aorta (aorta, aortic, thoracic), I74.19 — Embolism and thrombosis of other parts of aorta (aorta, aortic, specified site NEC), I74.2 — Embolism and thrombosis of arteries of the upper extremities (upper extremity), I74.3 — Embolism and thrombosis of arteries of the lower extremities (popliteal), I74.4 — Embolism and thrombosis of arteries of extremities, unspecified (artery, limb), I74.5 — Embolism and thrombosis of iliac artery (artery, iliac), I74.8 — Embolism and thrombosis of other arteries (spleen, splenic), I74.9 — Embolism and thrombosis of unspecified artery, I76 — Septic arterial embolism (septic), I78.8 — Other diseases of capillaries (capillary), I82.0 — Budd-Chiari syndrome (hepatic), I82.210 — Acute embolism and thrombosis of superior vena cava (vena cava, superior), I82.211 — Chronic embolism and thrombosis of superior vena cava (vena cava, superior, chronic), I82.220 — Acute embolism and thrombosis of inferior vena cava (vena cava, inferior), I82.221 — Chronic embolism and thrombosis of inferior vena cava (vena cava, inferior, chronic), I82.290 — Acute embolism and thrombosis of other thoracic veins (vein, innominate), I82.291 — Chronic embolism and thrombosis of other thoracic veins (vein, innominate, chronic), I82.3 — Embolism and thrombosis of renal vein (renal, vein), I82.40 — Acute embolism and thrombosis of unspecified deep veins of lower extremity (vein, deep), I82.41 — Acute embolism and thrombosis of femoral vein (vein, femoral), +273 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Gamma-glutamyl Transferase (GGT) Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of I81 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.

Run I81 with these 4 related codes in Claim Check

Hierarchy

Excludes2

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 07 — Diseases and Disorders of the Hepatobiliary System and Pancreas[MDC crossing]: “Diseases and Disorders of the Hepatobiliary System and Pancreas — 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. 2,488 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Block, blocked, portal (vein)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Embolism (multiple) (paradoxical), portal (vein)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Obstruction, obstructed, obstructive, portal (circulation) (vein)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Pseudoangioma[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel), liver (venous), portal vein[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Thrombosis, thrombotic (bland) (multiple) (progressive) (silent) (vessel), portal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "I81 — Portal vein thrombosis." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/i81-portal-vein-thrombosis

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Portal vein thrombosis

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.