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S66.412S vs S66.419S

S66.412S (Strain of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequela) compared with S66.419S (Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, sequela), from the official CMS tabular data. S66.412S and S66.419S code the same condition on opposite sides. MedCoder-derived

Relationship

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Laterality relationship

S66.412S
Left
Strain of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequela
↔
S66.419S
Unspecified
Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, 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. S66.412S and S66.419S 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

S66.412SStrain of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequelaS66.419SStrain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, sequela
Billing statusBillableBillable
ClassificationS00-T88 — Injury, poisoning and certain other consequences of external causesS00-T88 — Injury, poisoning and certain other consequences of external causes
DefinitionStrain of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequela is a billable ICD-10-CM diagnosis code (S66.412S).Strain of intrinsic muscle, fascia and tendon of unspecified thumb at wrist and hand level, sequela is a billable ICD-10-CM diagnosis code (S66.419S).
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