T25.639A — Corrosion of second degree of unspecified toe(s) (nail), initial encounter
Is T25.639A billable?
Yes, but T25.639A is an unspecified code. T25.639A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, T25.639A 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 T25.639A — the more specific alternatives are listed below.
T25.639A at a glance
| Code | T25.639A |
|---|---|
| Description | Corrosion of second degree of unspecified toe(s) (nail), 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 T25.639A?
In T25.639A, the 7th character A means initial encounter. The 7th character is required for T25.639A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does T25.639A group to?
T25.639A 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 T25.639A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T25.639, the nearest indexed parent of T25.639A. Use them to find the family, then select the specific code.
- Corrosion › toe › second degree (injury) (acid) (caustic) (chemical) (lime) (external) (internal)
Code first — inherited from T25.6
The underlying condition below must be sequenced before T25.639A. T25.639A 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 T25.639A to fully describe the condition. T25.639A 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 T25.639A to fully describe the condition. T25.639A is sequenced first.
Use additional code — inherited from T25.6
Report an additional code alongside T25.639A to fully describe the condition. T25.639A 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 T25.639A, but a patient may have both at the same time. When documentation supports it, T25.639A and the excluded code may both be reported.
How long has T25.639A existed?
T25.639A 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.