T33.1XXD
Superficial frostbite of neck, subsequent encounter
T33.1XXD (also written T331XXD) is a billable ICD-10-CM diagnosis code for superficial frostbite of neck, subsequent encounter. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 111 codes in category T33 (Superficial frostbite). The Alphabetic Index lists it under 1 entry. Its 7th character, D, means subsequent encounter. Its coding notes include a Use additional code instruction and 3 Excludes2 entries.
7th character
Category T33 requires a 7th character. T33.1 has only 4 characters, so a placeholder X fills the empty positions.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (1 note)
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (3 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Includes
Further defines or gives examples of the content of the category.
- frostbite with partial thickness skin loss
Notes
Also from chapter/block level (2 notes)
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
Alphabetic Index terms
Terms the official Alphabetic Index lists for T33.1. This code adds the 7th character. 1 entry