S66.503A — Unspecified injury of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level, initial encounter
Is S66.503A billable?
Yes, but S66.503A is an unspecified code. S66.503A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, S66.503A 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 S66.503A — the more specific alternatives are listed below.
More specific alternatives
- S66.001AUnspecified injury of long flexor muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter
- S66.201AUnspecified injury of extensor muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter
- S66.401AUnspecified injury of intrinsic muscle, fascia and tendon of right thumb at wrist and hand level, initial encounter
S66.503A at a glance
| Code | S66.503A |
|---|---|
| Description | Unspecified injury of intrinsic muscle, fascia and tendon of left middle finger at wrist and hand level, initial encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter |
What does the 7th character "A" mean in S66.503A?
In S66.503A, the 7th character A means initial encounter. The 7th character is required for S66.503A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S66.503A group to?
S66.503A 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 S66.503A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S66.50, the nearest indexed parent of S66.503A. Use them to find the family, then select the specific code.
- Injury › muscle › finger › index › intrinsic
- Injury › muscle › finger › little › intrinsic
- Injury › muscle › finger › middle › intrinsic
- Injury › muscle › finger › ring › intrinsic
Use additional code — inherited from Chapter 19
Report an additional code alongside S66.503A to fully describe the condition. S66.503A 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 S66.503A, but a patient may have both at the same time. When documentation supports it, S66.503A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S60-S69
The conditions below are not part of S66.503A, but a patient may have both at the same time. When documentation supports it, S66.503A and the excluded code may both be reported.
Excludes2 — not included here — inherited from S66
The conditions below are not part of S66.503A, but a patient may have both at the same time. When documentation supports it, S66.503A and the excluded code may both be reported.
- sprain of joints and ligaments of wrist and hand (S63.-)
Excludes2 — not included here — inherited from S66.5
The conditions below are not part of S66.503A, but a patient may have both at the same time. When documentation supports it, S66.503A and the excluded code may both be reported.
- injury of intrinsic muscle, fascia and tendon of thumb at wrist and hand level (S66.4-)
Code also — inherited from S66
Two codes may be needed to describe the condition fully. Whether S66.503A is sequenced first depends on the reason for the encounter.
- any associated open wound (S61.-)
How long has S66.503A existed?
S66.503A 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.