T21.79XD — Corrosion of third degree of other site of trunk, subsequent encounter
Is T21.79XD billable?
Yes — T21.79XD is billable for FY2027. T21.79XD is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. T21.79XD may be submitted for encounters from October 1, 2026 through September 30, 2027.
T21.79XD at a glance
| Code | T21.79XD |
|---|---|
| Description | Corrosion of third degree of other site of trunk, 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 T21.79XD?
In T21.79XD, the 7th character D means subsequent encounter. The 7th character is required for T21.79XD to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does T21.79XD group to?
T21.79XD 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 T21.79XD listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T21.79, the nearest indexed parent of T21.79XD. Use them to find the family, then select the specific code.
- Corrosion › trunk › specified site NEC › third degree (injury) (acid) (caustic) (chemical) (lime) (external) (internal)
Code first — inherited from T21.7
The underlying condition below must be sequenced before T21.79XD. T21.79XD describes a manifestation and cannot be the principal or first-listed diagnosis.
- (T51-T65) to identify chemical and intent
Use additional code — inherited from Chapter 19
Report an additional code alongside T21.79XD to fully describe the condition. T21.79XD is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Use additional code — inherited from T20-T25
Report an additional code alongside T21.79XD to fully describe the condition. T21.79XD is sequenced first.
Use additional code — inherited from T21.7
Report an additional code alongside T21.79XD to fully describe the condition. T21.79XD is sequenced first.
- external cause code to identify place (Y92)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T21.79XD, but a patient may have both at the same time. When documentation supports it, T21.79XD and the excluded code may both be reported.
Excludes2 — not included here — inherited from T21
The conditions below are not part of T21.79XD, but a patient may have both at the same time. When documentation supports it, T21.79XD and the excluded code may both be reported.
How long has T21.79XD existed?
T21.79XD 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.