2027 ICD-10-CM Diagnosis Code T33.1XXSSuperficial frostbite of neck, sequela

ICD-10-CM Codes›S00–T88›T33-T34›T33

ICD-10-CM T33.1XXS
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T33.1XXS is a billable ICD-10-CM diagnosis code for superficial frostbite of neck, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. Coders also document this condition as frostbite of neck. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of other external causes, sequela.

Code Identity

ICD-10-CM Code
T33.1XXS
Billable Status
Yes — Valid for Submission
Code Describes
Superficial frostbite of neck, sequela
Short Description
Superficial frostbite of neck, sequela
Same as the full description in the CMS dataset.
Parent Code
T33.1
Superficial frostbite of neck

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT33-T34Frostbite
CategoryT33Superficial frostbite
This CodeT33.1XXSSuperficial frostbite of neck, sequela

Present on Admission (POA)Billing

T33.1XXS is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Frostbite (T33-T34).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Frostbite of neck
  • Superficial frostbite
  • Superficial frostbite of neck

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Superficial frostbite (T33). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T33.1XXS: its own notes plus those printed at T33, block T33-T34, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From T33 Superficial frostbite applies to 111 codes
  • frostbite with partial thickness skin loss

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block T33-T34 Frostbite applies to 222 codes
  • hypothermia and other effects of reduced temperature (T68, T69.-)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • 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.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From T33 Superficial frostbite applies to 111 codes
  • The appropriate 7th character is to be added to each code from category T33
Values for category T33 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela this code

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ074
Effect of other external causes, sequela
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Frostbite

Frostbite is an injury to the body that is caused by freezing. It most often affects the nose, ears, cheeks, chin, fingers, or toes. Frostbite can permanently damage the body, and severe cases can lead to amputation.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert T33.1XXS to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
909.4 Late eff cert ext cause
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T33.1XXSOverview

What is the ICD-10 code for superficial frostbite of neck, sequela?

The ICD-10-CM code for superficial frostbite of neck, sequela is T33.1XXS (sometimes written as T331XXS). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T33.1XXS (Superficial frostbite of neck) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report superficial frostbite of neck, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character S in T33.1XXS mean?

The final character S makes this a sequela code: it reports a lingering problem that remains after the superficial frostbite of neck itself has resolved, not the original event.

What MS-DRG does T33.1XXS group to?

When superficial frostbite of neck, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 923, 922, with relative weights from 0.9980 to 1.6248 depending on complications. Higher weights mean higher Medicare reimbursement.

Is T33.1XXS exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for superficial frostbite of neck, sequela on inpatient claims. The code appears in the Frostbite (T33-T34) range of the CMS exempt list.