ICD-10 I81
Billable / Specific MCCPortal vein thrombosis
About ICD-10-CM I81
ICD-10-CM code I81 represents Portal vein thrombosis. This is a billable/specific code in the Circulatory System chapter (block I81). The 2026 edition of ICD-10-CM I81 became effective on October 1, 2025.
Coding Tips for I81
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
I81 is designated MCC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-MCC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag MCC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under I81. Per CMS ICD-10-CM Tabular 2026.
- Portal (vein) obstruction
Type 2 Excludes
Not included here, the excluded code is not part of I81, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- hepatic vein thrombosis (I82.0)
- phlebitis of portal vein (K75.1)
Inpatient DRG Impact, MCC
codes Portal vein thrombosis. As a Major Complication/Comorbidity (MCC), this can shift the DRG assignment to a higher-weighted category, substantial reimbursement impact.
Medicare LCD Coverage for I81
Local Coverage Determinations (LCDs) from CMS MACs that list I81 as a covered diagnosis.
Showing top 10 of 165 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I81.
5 Medicare
CPT Codes Commonly Billed with I81
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
Convert I81 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| I81 | 452 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To I81
Other codes in section I80-I89 (Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified).
ICD-10 I81, Billing FAQ
Is ICD-10 code I81 billable? +
Yes, I81 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to I81? +
ICD-10 I81 includes: Portal (vein) obstruction.
What codes are Type 2 Excludes for I81? +
Type 2 Excludes (may be coded together when both conditions exist): hepatic vein thrombosis (I82.0); phlebitis of portal vein (K75.1)
Is I81 a CC or MCC for inpatient DRG? +
Yes, this code is designated as MCC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with I81? +
Procedures frequently paired with I81 include: 81240, 81241, 81490.
What ICD-9 codes does I81 map to? +
Per CMS GEMs, I81 maps to ICD-9 codes: 452. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on July 16, 2026.
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