MCMCB Pro
I81

I81Portal vein thrombosis

Billable / specific codeICD-10-CM

I81 is a billable, specific ICD-10-CM code for portal vein thrombosis. It is valid for submission on a claim.

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

  • hepatic vein thrombosis (I82.0)
  • phlebitis of portal vein (K75.1)

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Portal (vein) obstruction

Risk adjustment

I81 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

I81 is named in 13 Medicare coverage policies 13 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A55717Billing and Coding: Lab: Flow Cytometry
  • A56464Billing and Coding: Flow Cytometry
  • A56541Billing and Coding: Biomarkers Overview
  • A56580Billing and Coding: Computerized Axial Tomography (CT), Thorax

How I81 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to I81.

  • Pseudoangioma
  • Block, blockedportal(vein)
  • Embolismportal(vein)
  • Obstruction, obstructed, obstructiveportal(circulation) (vein)
  • Thrombosis, thromboticportal
  • Thrombosis, thromboticliverportal vein

Questions about I81

Is I81 a billable ICD-10-CM code?
Yes. I81 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does I81 sit in the tabular list?
Diseases of the circulatory system (I00-I99), in the block Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified (I80-I89).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.