I80.9Phlebitis and thrombophlebitis of unspecified site

I80.9 is the ICD-10-CM diagnosis code for phlebitis and thrombophlebitis of unspecified site. It belongs to category I80 (phlebitis and thrombophlebitis), 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.

Within I80, choose I80.9 (of unspecified site) only when documentation doesn't support a more specific option: of superficial vessels of lower extremities (I80.0), of femoral vein (I80.1), of other and unspecified deep vessels of lower extremities (I80.2), of lower extremities, unspecified (I80.3) and of other sites (I80.8).

Code first: , if applicable: phlebitis and thrombophlebitis complicating abortion, ectopic or molar pregnancy (O00-O07, O08.7) and phlebitis and thrombophlebitis complicating pregnancy, childbirth and the puerperium (O22.-, O87.-).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 299 (Peripheral Vascular Disorders with MCC, relative weight 1.5842), DRG 300 (Peripheral Vascular Disorders with CC, relative weight 1.0464) and DRG 301 (Peripheral Vascular Disorders without CC/MCC, relative weight 0.7133), in MDC 05 (Diseases and Disorders of the Circulatory System), 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 451.9 (phlebitis and thrombophlebitis of unspecified site).