T79.A21A Traumatic compartment syndrome of right lower extremity, initial encounter

Billable ICD-10-CM code, FY2026.

Built from T79.A21 with 7th character A (initial encounter).

Applies from T79 Certain early complications of trauma, not elsewhere classified

Excludes2 (not included here)

• acute respiratory distress syndrome (J80)
• complications occurring during or following medical procedures (T80-T88)
• complications of surgical and medical care NEC (T80-T88)
• newborn respiratory distress syndrome (P22.0)

7th character note

• The appropriate 7th character is to be added to each code from category T79

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Applies from T79.A Traumatic compartment syndrome

Excludes1 (never code together)

• fibromyalgia (M79.7)
• nontraumatic compartment syndrome (M79.A-)

Excludes2 (not included here)

• traumatic ischemic infarction of muscle (T79.6)

Applies from T79.A2 Traumatic compartment syndrome of lower extremity

Applicable to

• Traumatic compartment syndrome of hip, buttock, thigh, leg, foot, and toes

Risk adjustment (HCC)

• CMS-HCC V22: HCC 173 — Traumatic Amputations and Complications
• ESRD V24: HCC 173

Code annotations containing back-references to T79.A21A

Back-references to T79.A

• Type 1 Excludes: M62.2 Nontraumatic ischemic infarction of muscle ("compartment syndrome (traumatic) (T79.A-)")
• Type 1 Excludes: M79.A Nontraumatic compartment syndrome ("compartment syndrome NOS (T79.A-)")
• Type 1 Excludes: M79.A Nontraumatic compartment syndrome ("traumatic compartment syndrome (T79.A-)")
• Type 2 Excludes: T79.6 Traumatic ischemia of muscle ("compartment syndrome (traumatic) (T79.A-)")

Nearby codes

• T79.A19A Traumatic compartment syndrome of unspecified upper extremity, initial encounter
• T79.A19D Traumatic compartment syndrome of unspecified upper extremity, subsequent encounter
• T79.A19S Traumatic compartment syndrome of unspecified upper extremity, sequela
• T79.A2 Traumatic compartment syndrome of lower extremity
• T79.A21 Traumatic compartment syndrome of right lower extremity
• T79.A21A Traumatic compartment syndrome of right lower extremity, initial encounter (this code)
• T79.A21D Traumatic compartment syndrome of right lower extremity, subsequent encounter
• T79.A21S Traumatic compartment syndrome of right lower extremity, sequela
• T79.A22 Traumatic compartment syndrome of left lower extremity
• T79.A22A Traumatic compartment syndrome of left lower extremity, initial encounter
• T79.A22D Traumatic compartment syndrome of left lower extremity, subsequent encounter