Portal vein thrombosis
In Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified (I80-I89), chapter 9: Diseases of the Circulatory System
- I81 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under I80-I89 below.
- As a secondary diagnosis it is an MCC (major complication), which can raise the MS-DRG payment. It doesn't count when the principal diagnosis is one of 202 closely related codes.
- Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
- AHRQ's Chronic Condition Indicator classes it as not chronic (an acute or short-term condition).
- 178 US deaths in 2024 had an underlying cause in category I81, per the National Vital Statistics System on CDC WONDER. Death records use WHO ICD-10, so the count is for the whole category.
Also indexed as: Block, portal; Embolism, portal; Obstruction, portal; Pseudoangioma; Thrombosis, liver, portal vein; Thrombosis, portal
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Instructional notes
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Covers hypertension with heart and kidney disease, coronary artery disease with angina, perioperative stroke, cerebrovascular sequelae, and acute myocardial infarction types and timing.
- Hypertension (page 50)
- Atherosclerotic Coronary Artery Disease and Angina (page 52)
- Intraoperative and Postprocedural Cerebrovascular Accident (page 53)
- Sequelae of Cerebrovascular Disease (page 53)
- Acute myocardial infarction (AMI) (page 54)
Other codes under I80-I89
Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified (I80-I89)
- I80Phlebitis and thrombophlebitis
- I81Portal vein thrombosis(this code)
- I82Other venous embolism and thrombosis
- I83Varicose veins of lower extremities
- I85Esophageal varices
- I86Varicose veins of other sites
- I87Other disorders of veins
- I88Nonspecific lymphadenitis
- I89Other noninfective disorders of lymphatic vessels and lymph nodes
I81 MS-DRGs
As the principal diagnosis, I81 groups to MS-DRG 441, 442, or 443 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
Related conditions
Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.
I81 is in Acute phlebitis; thrombophlebitis and thromboembolism (CIR033, its default category), with 127 codes. Others in it:
- I80.00 Phlebitis and thrombophlebitis of superficial vessels of unspecified lower extremity
- I80.01 Phlebitis and thrombophlebitis of superficial vessels of right lower extremity
- I80.02 Phlebitis and thrombophlebitis of superficial vessels of left lower extremity
- I80.03 Phlebitis and thrombophlebitis of superficial vessels of lower extremities, bilateral
- I80.10 Phlebitis and thrombophlebitis of unspecified femoral vein
- I80.11 Phlebitis and thrombophlebitis of right femoral vein
- I80.12 Phlebitis and thrombophlebitis of left femoral vein
- I80.13 Phlebitis and thrombophlebitis of femoral vein, bilateral
Medicare coverage articles listing I81
These 8 Medicare billing and coding articles list I81 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.
Other codes that refer to I81
Notes on these codes point to I81.
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
Deep Vein Thrombosis
Deep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. If the vein swells, the condition is called thrombophlebitis. A deep vein thrombosis can break loose and cause a serious problem in the lung, called a pulmonary embolism.
Read more about deep vein thrombosis on MedlinePlusLiver Diseases
Your liver is the largest organ inside your body. It helps your body digest food, store energy, and remove poisons. There are many kinds of liver diseases:
Read more about liver diseases on MedlinePlusCode history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.
ICD-9-CM equivalent
Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).
- 452 Portal vein thrombosis