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S56.591A vs S56.591S

S56.591A (Other injury of other extensor muscle, fascia and tendon at forearm level, right arm, initial encounter) compared with S56.591S (Other injury of other extensor muscle, fascia and tendon at forearm level, right arm, sequela), from the official CMS tabular data. S56.591A and S56.591S code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

S56.591A
Initial encounter
Other injury of other extensor muscle, fascia and tendon at forearm level, right arm, initial encounter
S56.591S
Sequela
Other injury of other extensor muscle, fascia and tendon at forearm level, right arm, sequela

Same underlying diagnosis, different encounter phase.

The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.

Source: ICD-10-CM Official Guidelines, Section I.C.19.a

Can these codes be reported together?

Same injury, other encounter phase. S56.591A and S56.591S code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

Side by side

S56.591AOther injury of other extensor muscle, fascia and tendon at forearm level, right arm, initial encounterS56.591SOther injury of other extensor muscle, fascia and tendon at forearm level, right arm, sequela
Billing statusBillableBillable
ClassificationS00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
DefinitionOther injury of other extensor muscle, fascia and tendon at forearm level, right arm, initial encounter is a billable ICD-10-CM diagnosis code (S56.591A).Other injury of other extensor muscle, fascia and tendon at forearm level, right arm, sequela is a billable ICD-10-CM diagnosis code (S56.591S).
7th characterThe appropriate 7th character is to be added to each code from category S56The appropriate 7th character is to be added to each code from category S56

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources