T33.819A — Superficial frostbite of unspecified ankle, initial encounter
Is T33.819A billable?
Yes, but T33.819A will trip a Medicare edit. T33.819A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists T33.819A under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
T33.819A at a glance
| Code | T33.819A |
|---|---|
| Description | Superficial frostbite of unspecified ankle, 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 T33.819A?
In T33.819A, the 7th character A means initial encounter. The 7th character is required for T33.819A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
What Medicare edits apply to T33.819A?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name T33.819A directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does T33.819A group to?
T33.819A 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.
- 922Other Injury, Poisoning and Toxic Effect Diagnoses with MCCmedical
- 923Other Injury, Poisoning and Toxic Effect Diagnoses without MCCmedical
As a secondary diagnosis, T33.819A is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG. It also carries Hospital-Acquired Condition category 05.
How is T33.819A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T33.81, the nearest indexed parent of T33.819A. Use them to find the family, then select the specific code.
- Frostbite › ankle (superficial)
Use additional code — inherited from Chapter 19
Report an additional code alongside T33.819A to fully describe the condition. T33.819A 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 T33.819A, but a patient may have both at the same time. When documentation supports it, T33.819A and the excluded code may both be reported.
Excludes2 — not included here — inherited from T33-T34
The conditions below are not part of T33.819A, but a patient may have both at the same time. When documentation supports it, T33.819A and the excluded code may both be reported.
How long has T33.819A existed?
T33.819A 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.