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S66.590 vs S66.591

S66.590 (Other injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level) compared with S66.591 (Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level), from the official CMS tabular data. S66.590 and S66.591 code the same condition on opposite sides.

Relationship

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Laterality relationship

S66.590
Right
Other injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level
↔
S66.591
Left
Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level

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. S66.590 and S66.591 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

S66.590Other injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand levelS66.591Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level
Billing statusNon-billable header

Report instead: S66.590A, S66.590D, S66.590S

Non-billable header

Report instead: S66.591A, S66.591D, S66.591S

ClassificationS00-T88 — Injury, poisoning and certain other consequences of external causesS00-T88 — Injury, poisoning and certain other consequences of external causes
DefinitionOther injury of intrinsic muscle, fascia and tendon of right index finger at wrist and hand level is a non-billable ICD-10-CM category code (S66.590).Other injury of intrinsic muscle, fascia and tendon of left index finger at wrist and hand level is a non-billable ICD-10-CM category code (S66.591).
7th characterThe appropriate 7th character is to be added to each code from category S66The appropriate 7th character is to be added to each code from category S66
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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