ICD-10 S66.29
Non-Billable HeaderOther specified injury of extensor muscle, fascia and tendon of thumb at wrist and hand level
About ICD-10-CM S66.29
ICD-10-CM code S66.29 represents Other specified injury of extensor muscle, fascia and tendon of thumb 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 S66.29 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 S66.29
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.
Medicare LCD Coverage for S66.29
Local Coverage Determinations (LCDs) from CMS MACs that list S66.29 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 S66.29.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but S66.29 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with S66.29
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 S66.29
Other codes in section S60-S69 (Injuries to the wrist, hand and fingers).
ICD-10 S66.29, Billing FAQ
Is ICD-10 code S66.29 billable? +
No, S66.29 is a non-billable header code. Use a more specific child code from block S66 when submitting claims.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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