I81Portal vein thrombosis

I81 is the ICD-10-CM diagnosis code for portal vein thrombosis. It belongs to block I80-I89 (diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The conditions in its Excludes2 note aren't part of I81, but may be coded alongside it if the patient has both: hepatic vein thrombosis (I82.0) and phlebitis of portal vein (K75.1).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 441 (Disorders of Liver Except Malignancy, Cirrhosis or Alcoholic Hepatitis with MCC, relative weight 1.8219), DRG 442 (Disorders of Liver Except Malignancy, Cirrhosis or Alcoholic Hepatitis with CC, relative weight 0.9602) and DRG 443 (Disorders of Liver Except Malignancy, Cirrhosis or Alcoholic Hepatitis without CC/MCC, relative weight 0.6885), in MDC 07 (Diseases and Disorders of the Hepatobiliary System and Pancreas), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 452 (portal vein thrombosis).