T34.09XA ICD-10-CM Code: Frostbite with tissue necrosis of other part of head, initial encounter

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T34.09XA in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on T34.09XA itself; “inherited from” names the category or block whose note applies here.

7th Character Guide

"The appropriate 7th character is to be added to each code from category T34"

• A — initial encounter (this page’s code)
• 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

T34.09XA, T34.09XD, T34.09XS

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 T34.09XA

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

Before you code T34.09XA

1. A 7th character is required in this family. Confirm the documented encounter: initial (active treatment), subsequent (healing or recovery phase), or sequela. This page’s code carries “A”. “Initial” means active treatment, not the first visit (Guidelines I.C.19.a).

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

2. T34.09XA’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

   Guide: Combination codes →

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. 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 T34.09XA. 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).

The associated condition or complication

Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

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 T34.09XA(1 note)

  Coding workflow: The conditions named in this note are not included in T34.09XA. 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

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.

Don’t confuse T34.09XA with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of T34.09XA — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• T34.09XD— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a subsequent encounter moves the case to T34.09XD.

  Full comparison: T34.09XA vs T34.09XD →

• T34.09XS— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a sequela moves the case to T34.09XS.

  Full comparison: T34.09XA vs T34.09XS →

• T68— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypothermia and other effects of reduced temperature adds T68; it is not part of this code and both may be reported when both are documented.

  Full comparison: T34.09XA vs T68 →

• T69— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypothermia and other effects of reduced temperature adds T69; it is not part of this code and both may be reported when both are documented.

  Full comparison: T34.09XA vs T69 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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 T34.09XA 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 (via T34.-).

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 (via T34.-), S00 — Superficial injury of head (via T34.-), S00-S09 — Injuries to the head (S00-S09) (via T34.-), S01 — Open wound of head (via T34.-), S02 — Fracture of skull and facial bones (via T34.-), S03 — Dislocation and sprain of joints and ligaments of head (via T34.-), S04 — Injury of cranial nerve (via T34.-), S05 — Injury of eye and orbit (via T34.-), S06 — Intracranial injury (via T34.-), S07 — Crushing injury of head (via T34.-), S08 — Avulsion and traumatic amputation of part of head (via T34.-), S09 — Other and unspecified injuries of head (via T34.-), S10 — Superficial injury of neck (via T34.-), S10-S19 — Injuries to the neck (S10-S19) (via T34.-), S11 — Open wound of neck (via T34.-), S12 — Fracture of cervical vertebra and other parts of neck (via T34.-), S13 — Dislocation and sprain of joints and ligaments at neck level (via T34.-), S14 — Injury of nerves and spinal cord at neck level (via T34.-), S15 — Injury of blood vessels at neck level (via T34.-), S16 — Injury of muscle, fascia and tendon at neck level (via T34.-), +92 more.

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 38 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 922 (MDC 21), DRG 923 (MDC 21).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INJ021 — Effect of other external causes, initial encounter (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

T33.62XA — Superficial frostbite of left hip and thigh, initial encounter, T33.70XA — Superficial frostbite of unspecified knee and lower leg, initial encounter, T33.71XA — Superficial frostbite of right knee and lower leg, initial encounter, T33.72XA — Superficial frostbite of left knee and lower leg, initial encounter, T33.90XA — Superficial frostbite of unspecified sites, initial encounter, T33.99XA — Superficial frostbite of other sites, initial encounter, T34.011A — Frostbite with tissue necrosis of right ear, initial encounter, T34.012A — Frostbite with tissue necrosis of left ear, initial encounter, T34.019A — Frostbite with tissue necrosis of unspecified ear, initial encounter, T34.02XA — Frostbite with tissue necrosis of nose, initial encounter, T34.1XXA — Frostbite with tissue necrosis of neck, initial encounter, T34.2XXA — Frostbite with tissue necrosis of thorax, initial encounter, T34.3XXA — Frostbite with tissue necrosis of abdominal wall, lower back and pelvis, initial encounter, T34.40XA — Frostbite with tissue necrosis of unspecified arm, initial encounter, T34.41XA — Frostbite with tissue necrosis of right arm, initial encounter, T34.42XA — Frostbite with tissue necrosis of left arm, initial encounter, T34.60XA — Frostbite with tissue necrosis of unspecified hip and thigh, initial encounter, T34.61XA — Frostbite with tissue necrosis of right hip and thigh, initial encounter, T34.62XA — Frostbite with tissue necrosis of left hip and thigh, initial encounter, T34.70XA — Frostbite with tissue necrosis of unspecified knee and lower leg, initial encounter, +17 more

Same injury, other encounter phase

Same injury, coded at a different phase of treatment via the 7th character.

T34.09XD — Frostbite with tissue necrosis of other part of head, subsequent encounterCompare T34.09XA vs T34.09XD →, T34.09XS — Frostbite with tissue necrosis of other part of head, sequelaCompare T34.09XA vs T34.09XS →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Effect of other external causes, initial encounter).

T33.829A — Superficial frostbite of unspecified foot, initial encounter, T33.831A — Superficial frostbite of right toe(s), initial encounter, T33.832A — Superficial frostbite of left toe(s), initial encounter, T33.839A — Superficial frostbite of unspecified toe(s), initial encounter, T33.90XA — Superficial frostbite of unspecified sites, initial encounter, T33.99XA — Superficial frostbite of other sites, initial encounter, T34.011A — Frostbite with tissue necrosis of right ear, initial encounter, T34.012A — Frostbite with tissue necrosis of left ear, initial encounter, T34.019A — Frostbite with tissue necrosis of unspecified ear, initial encounter, T34.02XA — Frostbite with tissue necrosis of nose, initial encounter, T34.1XXA — Frostbite with tissue necrosis of neck, initial encounter, T34.2XXA — Frostbite with tissue necrosis of thorax, initial encounter, T34.3XXA — Frostbite with tissue necrosis of abdominal wall, lower back and pelvis, initial encounter, T34.40XA — Frostbite with tissue necrosis of unspecified arm, initial encounter, T34.41XA — Frostbite with tissue necrosis of right arm, initial encounter, T34.42XA — Frostbite with tissue necrosis of left arm, initial encounter, T34.511A — Frostbite with tissue necrosis of right wrist, initial encounter, T34.512A — Frostbite with tissue necrosis of left wrist, initial encounter, T34.519A — Frostbite with tissue necrosis of unspecified wrist, initial encounter, T34.521A — Frostbite with tissue necrosis of right hand, initial encounter, +149 more

Contextual Map

Every relationship of T34.09XA 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 T34.09XA with these 9 related codes in Claim Check

Hierarchy

• S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T33-T34 — Frostbite[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• T07 — Unspecified multiple injuries[Excludes1](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes (112)

• I73 — Other peripheral vascular diseases[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S00 — Superficial injury of head[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S00-S09 — Injuries to the head (S00-S09)[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S01 — Open wound of head[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S02 — Fracture of skull and facial bones[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S03 — Dislocation and sprain of joints and ligaments of head[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S04 — Injury of cranial nerve[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S05 — Injury of eye and orbit[Excludes2](via T34.-): “frostbite (T33-T34)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• and 104 more

Clinical classification (CCSR)

• INJ021 — Effect of other external causes, initial encounter[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 922 — OTHER INJURY, POISONING AND TOXIC EFFECT DIAGNOSES WITH MCC[MS-DRG]: “OTHER INJURY, POISONING AND TOXIC EFFECT DIAGNOSES WITH MCC (MDC 21)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 923 — OTHER INJURY, POISONING AND TOXIC EFFECT DIAGNOSES WITHOUT MCC[MS-DRG]: “OTHER INJURY, POISONING AND TOXIC EFFECT DIAGNOSES WITHOUT MCC (MDC 21)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 21 — Injuries, Poisonings and Toxic Effects of Drugs[MDC crossing]: “Injuries, Poisonings and Toxic Effects of Drugs — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 32,029 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

• T34 — Frostbite with tissue necrosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.0 — Frostbite with tissue necrosis of head[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.01 — Frostbite with tissue necrosis of ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.011 — Frostbite with tissue necrosis of right ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.011A — Frostbite with tissue necrosis of right ear, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.011D — Frostbite with tissue necrosis of right ear, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.011S — Frostbite with tissue necrosis of right ear, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T34.012 — Frostbite with tissue necrosis of left ear[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

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

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

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T34.09XA in its code family, with their registry titles.

• T34.02 — Frostbite with tissue necrosis of nose
• T34.02XA — Frostbite with tissue necrosis of nose, initial encounter
• T34.02XD — Frostbite with tissue necrosis of nose, subsequent encounter
• T34.02XS — Frostbite with tissue necrosis of nose, sequela
• T34.09 — Frostbite with tissue necrosis of other part of head
• T34.09XD — Frostbite with tissue necrosis of other part of head, subsequent encounter
• T34.09XS — Frostbite with tissue necrosis of other part of head, sequela
• T34.1 — Frostbite with tissue necrosis of neck
• T34.1XXA — Frostbite with tissue necrosis of neck, initial encounter
• T34.1XXD — Frostbite with tissue necrosis of neck, subsequent encounter

View all codes in the T34 family