S66.402S — Unspecified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequela
Is S66.402S billable?
Yes, but S66.402S is an unspecified code. S66.402S is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, S66.402S is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting S66.402S — the more specific alternatives are listed below.
S66.402S at a glance
| Code | S66.402S |
|---|---|
| Description | Unspecified injury of intrinsic muscle, fascia and tendon of left thumb at wrist and hand level, sequela |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "S" | sequela |
What does the 7th character "S" mean in S66.402S?
In S66.402S, the 7th character S means sequela. The 7th character is required for S66.402S to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S66.402S group to?
S66.402S sits in MDC 21 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 913Traumatic Injury with MCCmedical
- 914Traumatic Injury without MCCmedical
How is S66.402S listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S66.40, the nearest indexed parent of S66.402S. Use them to find the family, then select the specific code.
- Injury › muscle › thumb › intrinsic
Use additional code — inherited from Chapter 19
Report an additional code alongside S66.402S to fully describe the condition. S66.402S is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of S66.402S, but a patient may have both at the same time. When documentation supports it, S66.402S and the excluded code may both be reported.
Excludes2 — not included here — inherited from S60-S69
The conditions below are not part of S66.402S, but a patient may have both at the same time. When documentation supports it, S66.402S and the excluded code may both be reported.
Excludes2 — not included here — inherited from S66
The conditions below are not part of S66.402S, but a patient may have both at the same time. When documentation supports it, S66.402S and the excluded code may both be reported.
- sprain of joints and ligaments of wrist and hand (S63.-)
Code also — inherited from S66
Two codes may be needed to describe the condition fully. Whether S66.402S is sequenced first depends on the reason for the encounter.
- any associated open wound (S61.-)
How long has S66.402S existed?
S66.402S has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.