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T33 ICD-10-CM Code: Superficial frostbite

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

7th character
Required — characters A · D · S
Tabular directives
1 inclusion term · 1 Excludes2

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T33 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on T33 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • frostbite with partial thickness skin loss

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from T33-T34

7th Character Guide

"The appropriate 7th character is to be added to each code from category T33"

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

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

T33-T34, T33.011A, T33.011D, T33.011S, T33.012A, T33.012D, T33.012S, T33.019A

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Coder workflow for T33

MedCoder structured workflow — derived from this code’s own official record

Before you code T33

  1. T33 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewT33.0, T33.1, T33.2, T33.3, T33.4, T33.5, T33.6, T33.7, T33.8, T33.9

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. A 7th character is required in this family. Confirm the documented encounter: initial (active treatment), subsequent (healing or recovery phase), or sequela. T33 is not valid without one. “Initial” means active treatment, not the first visit (Guidelines I.C.19.a).

    See the 7th Character Guide · Guide: 7th characters: initial, subsequent, sequela →

  3. Confirm the injury type, the anatomical site at the most specific level documented, laterality where the family codes it, and the encounter for the 7th character. Each injury is coded separately unless the classification provides a combination code, and a superficial injury is not coded when a more severe injury of the same site is documented. Injury chapter guidelines (Guidelines I.C.19.b, I.C.19.b.1).

    Guide: 7th characters: initial, subsequent, sequela →

Choose the right path

  1. Does the documentation support one of the more specific codes beneath T33?
    Yes → Select that code and continue the checks below on its own page.
    No → T33 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewT33.0, T33.1, T33.2, T33.3, T33.4, T33.5, T33.6, T33.7, T33.8, T33.9

  2. Is the encounter phase documented — active treatment, healing or recovery, or a sequela?
    Yes → Assign the matching 7th character; the variant codes are in the 7th Character Guide.
    No → The code is invalid without its 7th character — query for the missing element.

Consider T33. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Anatomical site
At the most specific level the record states; a site the classification separates cannot be assumed from a procedure or a measurement.
Encounter type
Active treatment, healing or recovery phase, or sequela — the basis of the 7th character (Guidelines I.C.19.a).
External cause, place and activity
For the external cause codes reported with the injury or poisoning, where documented (Guidelines I.C.20.a).

Official instructions as workflow

  • Excludes2 — not part of T33(1 note)

    Coding workflow: The conditions named in this note are not included in T33. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareT68, T69

    See the official tabular notes · Guidelines I.A.12.b

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: The patient returns during the healing or recovery phase after active treatment of the same condition.

Coding question: Which 7th character applies?

Path: Review the official 7th-character definitions for this family in the 7th Character Guide.

Reason: “Initial encounter” means active treatment, not the first visit; care during recovery takes “subsequent encounter”, and a complication arising from the original condition takes “sequela” (Guidelines I.C.19.a).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Superficial frostbite is a non-billable ICD-10-CM category code (T33). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name T33 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: T07 — Unspecified multiple injuries.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 112 Excludes2 notes across 2 chapters: I73 — Other peripheral vascular diseases, S00 — Superficial injury of head, S00-S09 — Injuries to the head (S00-S09), S01 — Open wound of head, S02 — Fracture of skull and facial bones, S03 — Dislocation and sprain of joints and ligaments of head, S04 — Injury of cranial nerve, S05 — Injury of eye and orbit, S06 — Intracranial injury, S07 — Crushing injury of head, S08 — Avulsion and traumatic amputation of part of head, S09 — Other and unspecified injuries of head, S10 — Superficial injury of neck, S10-S19 — Injuries to the neck (S10-S19), S11 — Open wound of neck, S12 — Fracture of cervical vertebra and other parts of neck, S13 — Dislocation and sprain of joints and ligaments at neck level, S14 — Injury of nerves and spinal cord at neck level, S15 — Injury of blood vessels at neck level, S16 — Injury of muscle, fascia and tendon at neck level, +92 more.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Contextual Map

Every relationship of T33 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run T33 with these 11 related codes in Claim Check

Hierarchy

Excludes2

  • T68 — Hypothermia[Excludes2]: “hypothermia and other effects of reduced temperature (T68, T69.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • T69 — Other effects of reduced temperature[Excludes2]: “hypothermia and other effects of reduced temperature (T68, T69.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes1 notes

Referenced by Excludes2 notes (112)

Nearest codes (162)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Can T33 be billed directly?

No. T33 (Superficial frostbite) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Does T33 require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T33; A: initial encounter; D: subsequent encounter; S: sequela.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "T33 — Superficial frostbite." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/t33-superficial-frostbite

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Superficial frostbite

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T33 in its code family, with their registry titles.