T21.55XA — Corrosion of first degree of buttock, initial encounter
Is T21.55XA billable?
Yes — T21.55XA is billable for FY2027. T21.55XA is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. T21.55XA may be submitted for encounters from October 1, 2026 through September 30, 2027.
T21.55XA at a glance
| Code | T21.55XA |
|---|---|
| Description | Corrosion of first degree of buttock, 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 T21.55XA?
In T21.55XA, the 7th character A means initial encounter. The 7th character is required for T21.55XA to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does T21.55XA group to?
T21.55XA sits in MDC 22 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 935Non-Extensive Burnsmedical
How is T21.55XA listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T21.55, the nearest indexed parent of T21.55XA. Use them to find the family, then select the specific code.
- Corrosion › buttock › first degree (injury) (acid) (caustic) (chemical) (lime) (external) (internal)
Inclusion terms
Alternative wording in documentation that is classified to T21.55XA.
- Corrosion of first degree of anus
Code first — inherited from T21.5
The underlying condition below must be sequenced before T21.55XA. T21.55XA 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 T21.55XA to fully describe the condition. T21.55XA 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 T21.55XA to fully describe the condition. T21.55XA is sequenced first.
Use additional code — inherited from T21.5
Report an additional code alongside T21.55XA to fully describe the condition. T21.55XA 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 T21.55XA, but a patient may have both at the same time. When documentation supports it, T21.55XA and the excluded code may both be reported.
Excludes2 — not included here — inherited from T21
The conditions below are not part of T21.55XA, but a patient may have both at the same time. When documentation supports it, T21.55XA and the excluded code may both be reported.
How long has T21.55XA existed?
T21.55XA 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.