S04.21XD — Injury of trochlear nerve, right side, subsequent encounter
Is S04.21XD billable?
Yes — S04.21XD is billable for FY2027. S04.21XD is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. S04.21XD may be submitted for encounters from October 1, 2026 through September 30, 2027.
S04.21XD at a glance
| Code | S04.21XD |
|---|---|
| Description | Injury of trochlear nerve, right side, subsequent encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "D" | subsequent encounter |
What does the 7th character "D" mean in S04.21XD?
In S04.21XD, the 7th character D means subsequent encounter. The 7th character is required for S04.21XD to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does S04.21XD group to?
S04.21XD sits in MDC 23 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.
- 949Aftercare with CC/MCCmedical
- 950Aftercare without CC/MCCmedical
How is S04.21XD listed in the Alphabetic Index?
The Alphabetic Index lists these routes under S04.2, the nearest indexed parent of S04.21XD. Use them to find the family, then select the specific code.
- Injury › nerve NEC › trochlear
- Injury › nerve NEC › trochlear › contusion
- Injury › nerve NEC › trochlear › laceration
- Injury › nerve NEC › trochlear › specified type NEC
Code first — inherited from S04
The underlying condition below must be sequenced before S04.21XD. S04.21XD describes a manifestation and cannot be the principal or first-listed diagnosis.
- any associated intracranial injury (S06.-)
Use additional code — inherited from Chapter 19
Report an additional code alongside S04.21XD to fully describe the condition. S04.21XD 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 S04.21XD, but a patient may have both at the same time. When documentation supports it, S04.21XD and the excluded code may both be reported.
Excludes2 — not included here — inherited from S00-S09
The conditions below are not part of S04.21XD, but a patient may have both at the same time. When documentation supports it, S04.21XD and the excluded code may both be reported.
- burns and corrosions (T20-T32)
- effects of foreign body in ear (T16)
- effects of foreign body in larynx (T17.3)
- effects of foreign body in mouth NOS (T18.0)
- effects of foreign body in nose (T17.0-T17.1)
- effects of foreign body in pharynx (T17.2)
- effects of foreign body on external eye (T15.-)
- frostbite (T33-T34)
- insect bite or sting, venomous (T63.4)
Code also — inherited from S00-S09
Two codes may be needed to describe the condition fully. Whether S04.21XD is sequenced first depends on the reason for the encounter.
- for any associated infection
Code also — inherited from S04
Two codes may be needed to describe the condition fully. Whether S04.21XD is sequenced first depends on the reason for the encounter.
How long has S04.21XD existed?
S04.21XD 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.