I82.509 Chronic embolism and thrombosis of unspecified deep veins of unspecified lower extremity

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

Applies from I82 Other venous embolism and thrombosis

Excludes2 (not included here)

• venous embolism and thrombosis (of):
• cerebral (I63.6, I67.6)
• coronary (I21-I25)
• intracranial and intraspinal, septic or NOS (G08)
• intracranial, nonpyogenic (I67.6)
• intraspinal, nonpyogenic (G95.1)
• mesenteric (K55.0-)
• portal (I81)
• pulmonary (I26.-)

Code first

• venous embolism and thrombosis complicating:
• abortion, ectopic or molar pregnancy (O00-O07, O08.7)
• pregnancy, childbirth and the puerperium (O22.-, O87.-)

Applies from I82.5 Chronic embolism and thrombosis of deep veins of lower extremity

Excludes1 (never code together)

• personal history of venous embolism and thrombosis (Z86.718)

Use additional code

• code, if applicable, for associated long-term (current) use of anticoagulants (Z79.01)

Applies from I82.50 Chronic embolism and thrombosis of unspecified deep veins of lower extremity

Excludes1 (never code together)

• chronic embolism and thrombosis of unspecified deep veins of distal lower extremity (I82.5Z-)
• chronic embolism and thrombosis of unspecified deep veins of proximal lower extremity (I82.5Y-)

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)

• 453.50 Chronic venous embolism and thrombosis of unspecified deep vessels of lower extremity (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.

Code annotations containing back-references to I82.509

Back-references to I82.5

• Type 1 Excludes: I80 Phlebitis and thrombophlebitis ("venous embolism and thrombosis of lower extremities (I82.4-, I82.5-, I82.81-)")
• Use Additional: O22.3 Deep phlebothrombosis in pregnancy ("code to identify the deep vein thrombosis (I82.4-, I82.5-, I82.62-, I82.72-)")
• Use Additional: O87.1 Deep phlebothrombosis in the puerperium ("code to identify the deep vein thrombosis (I82.4-, I82.5-, I82.62-, I82.72-)")

Nearby codes

• I82.5 Chronic embolism and thrombosis of deep veins of lower extremity
• I82.50 Chronic embolism and thrombosis of unspecified deep veins of lower extremity
• I82.501 Chronic embolism and thrombosis of unspecified deep veins of right lower extremity
• I82.502 Chronic embolism and thrombosis of unspecified deep veins of left lower extremity
• I82.503 Chronic embolism and thrombosis of unspecified deep veins of lower extremity, bilateral
• I82.509 Chronic embolism and thrombosis of unspecified deep veins of unspecified lower extremity (this code)
• I82.51 Chronic embolism and thrombosis of femoral vein
• I82.511 Chronic embolism and thrombosis of right femoral vein
• I82.512 Chronic embolism and thrombosis of left femoral vein
• I82.513 Chronic embolism and thrombosis of femoral vein, bilateral
• I82.519 Chronic embolism and thrombosis of unspecified femoral vein