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S56.991S vs S56.999S

S56.991S (Other injury of unspecified muscles, fascia and tendons at forearm level, right arm, sequela) compared with S56.999S (Other injury of unspecified muscles, fascia and tendons at forearm level, unspecified arm, sequela), from the official CMS tabular data. S56.991S and S56.999S code the same condition on opposite sides. MedCoder-derived

Relationship

Review

Laterality relationship

S56.991S
Right
Other injury of unspecified muscles, fascia and tendons at forearm level, right arm, sequela
↔
S56.999S
Unspecified
Other injury of unspecified muscles, fascia and tendons at forearm level, unspecified arm, sequela

Same condition; these differ only in which side is documented.

These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.

Source: ICD-10-CM tabular list (laterality variant derived from the code title)

Can these codes be reported together?

Same condition, opposite side. S56.991S and S56.999S name the same condition on opposite sides of the body.

Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

Side by side

S56.991SOther injury of unspecified muscles, fascia and tendons at forearm level, right arm, sequelaS56.999SOther injury of unspecified muscles, fascia and tendons at forearm level, unspecified arm, sequela
Billing statusBillableBillable
ClassificationS00-T88 — Injury, poisoning and certain other consequences of external causesS00-T88 — Injury, poisoning and certain other consequences of external causes
DefinitionOther injury of unspecified muscles, fascia and tendons at forearm level, right arm, sequela is a billable ICD-10-CM diagnosis code (S56.991S).Other injury of unspecified muscles, fascia and tendons at forearm level, unspecified arm, sequela is a billable ICD-10-CM diagnosis code (S56.999S).
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
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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources