S45.991A vs S45.999A

S45.991A (Other specified injury of unspecified blood vessel at shoulder and upper arm level, right arm, initial encounter) compared with S45.999A (Other specified injury of unspecified blood vessel at shoulder and upper arm level, unspecified arm, initial encounter), from the official CMS tabular data. S45.991A and S45.999A code the same condition on opposite sides. MedCoder-derived

Relationship

Review

Laterality relationship

S45.991A

Right

Other specified injury of unspecified blood vessel at shoulder and upper arm level, right arm, initial encounter

↔

S45.999A

Unspecified

Other specified injury of unspecified blood vessel at shoulder and upper arm level, unspecified arm, initial encounter

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. S45.991A and S45.999A 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

	S45.991AOther specified injury of unspecified blood vessel at shoulder and upper arm level, right arm, initial encounter	S45.999AOther specified injury of unspecified blood vessel at shoulder and upper arm level, unspecified arm, initial encounter
Billing status	Billable	Billable
Classification	S00-T88 — Injury, poisoning and certain other consequences of external causes	S00-T88 — Injury, poisoning and certain other consequences of external causes
Definition	Other specified injury of unspecified blood vessel at shoulder and upper arm level, right arm, initial encounter is a billable ICD-10-CM diagnosis code (S45.991A).	Other specified injury of unspecified blood vessel at shoulder and upper arm level, unspecified arm, initial encounter is a billable ICD-10-CM diagnosis code (S45.999A).
7th character	The appropriate 7th character is to be added to each code from category S45	The appropriate 7th character is to be added to each code from category S45
Includes	injuries of axilla injuries of scapular region	injuries of axilla injuries of scapular region

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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