ICD-10 S66
Non-Billable HeaderInjury of muscle, fascia and tendon at wrist and hand level
About ICD-10-CM S66
ICD-10-CM code S66 represents Injury of muscle, fascia and tendon at wrist and hand level. This is a non-billable header code in the Injury, Poisoning, and External Causes chapter (block S66). The 2026 edition of ICD-10-CM S66 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Coding Tips for S66
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
Injury codes require a 7th character: A (initial encounter, active treatment), D (subsequent, healing/recovery), S (sequela, late effect of original injury). Codes with fewer than 6 characters need the placeholder X to bring them to 6 characters before adding the 7th. Wrong or missing 7th character is the #1 cause of injury claim denials.
Type 2 Excludes
Not included here, the excluded code is not part of S66, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- sprain of joints and ligaments of wrist and hand (S63.-)
Coding Notes
Code Also
- any associated open wound (S61.-)
Seven Chr Note
- The appropriate 7th character is to be added to each code from category S66
Medicare LCD Coverage for S66
Local Coverage Determinations (LCDs) from CMS MACs that list S66 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing S66.
2 Cigna
CPT Codes Commonly Billed with S66
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To S66
Other codes in section S60-S69 (Injuries to the wrist, hand and fingers).
ICD-10 S66, Billing FAQ
Is ICD-10 code S66 billable? +
No, S66 is a non-billable header code. Use a more specific child code from block S66 when submitting claims.
What codes are Type 2 Excludes for S66? +
Type 2 Excludes (may be coded together when both conditions exist): sprain of joints and ligaments of wrist and hand (S63.-)
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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