I80.299 Phlebitis and thrombophlebitis of other deep vessels of unspecified lower extremity

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from I80 Phlebitis and thrombophlebitis

Includes

• endophlebitis
• inflammation, vein
• periphlebitis
• suppurative phlebitis

Excludes1 (never code together)

• venous embolism and thrombosis of lower extremities (I82.4-, I82.5-, I82.81-)

Code first

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

Risk adjustment (HCC)

• CMS-HCC V28: HCC 267 — Deep Vein Thrombosis and Pulmonary Embolism
• CMS-HCC V22: HCC 108 — Vascular Disease
• RxHCC V08: HCC 215 — Venous Thromboembolism
• ESRD V24: HCC 108

MS-DRG index

Defines the logic of DRG(s) 299-301 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 451.19 Phlebitis and thrombophlebitis of deep veins of lower extremities, other (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Unspecified code (laterality): Unspecified codes for which a more specific code identifying laterality (right, left, bilateral) exists within the same code family.

Diagnosis Index entries for I80.299

• Thrombophlebitis › lower extremity

Nearby codes

• I80.259 Phlebitis and thrombophlebitis of unspecified calf muscular vein
• I80.29 Phlebitis and thrombophlebitis of other deep vessels of lower extremities
• I80.291 Phlebitis and thrombophlebitis of other deep vessels of right lower extremity
• I80.292 Phlebitis and thrombophlebitis of other deep vessels of left lower extremity
• I80.293 Phlebitis and thrombophlebitis of other deep vessels of lower extremity, bilateral
• I80.299 Phlebitis and thrombophlebitis of other deep vessels of unspecified lower extremity (this code)
• I80.3 Phlebitis and thrombophlebitis of lower extremities, unspecified
• I80.8 Phlebitis and thrombophlebitis of other sites
• I80.9 Phlebitis and thrombophlebitis of unspecified site