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T32.99 ICD-10-CM Code: Corrosions involving 90% or more of body surface with 90% or more third degree corrosion

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 162

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 927 — EXTENSIVE BURNS OR FULL THICKNESS BURNS WITH MV >96 HOURS WITH SKIN GRAFT (MDC 22)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 385 — Severe Skin Burn

Other models: CMS-HCC V22 HCC 162

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Code Overview

Corrosions involving 90% or more of body surface with 90% or more third degree corrosion is a billable ICD-10-CM diagnosis code (T32.99).

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

Indexed Clinical Terms (2)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Official Coding Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 19: Injury, poisoning, and certain other consequences of external causes (S00-T88)

6) Burns and corrosions classified according to extent of body surface involved Assign codes from category T31, Burns classified according to extent of body surface involved, or T32, Corrosions classified according to extent of body surface involved, for acute burns or corrosions when the site of the burn or corrosion is not specified or when there is a need for additional data. It is advisable to use category T31 as additional coding when needed to provide data for evaluating burn mortality, such as that needed by burn units. It is also advisable to use category T31 as an additional code for reporting purposes when there is mention of a third- degree burn involving 20 percent or more of the body surface. Codes from categories T31 and T32 should not be used for sequelae of burns or corrosions.

Chapter 19: Injury, poisoning, and certain other consequences of external causes (S00-T88)

Categories T31 and T32 are based on the classic “rule of nines” in estimating body surface involved: head and neck are assigned nine percent, each arm nine percent, each leg 18 percent, the anterior trunk 18 percent, posterior trunk 18 percent, and genitalia one percent. Providers may change these percentage assignments where necessary to accommodate infants and children who have proportionately larger heads

Verify Before Coding

  • MCC 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

Other codes that name T32.99 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 T32.-).

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

Referenced by 119 Excludes2 notes: S00 — Superficial injury of head (via T32.-), S00-S09 — Injuries to the head (S00-S09) (via T32.-), S01 — Open wound of head (via T32.-), S02 — Fracture of skull and facial bones (via T32.-), S03 — Dislocation and sprain of joints and ligaments of head (via T32.-), S04 — Injury of cranial nerve (via T32.-), S05 — Injury of eye and orbit (via T32.-), S06 — Intracranial injury (via T32.-), S07 — Crushing injury of head (via T32.-), S08 — Avulsion and traumatic amputation of part of head (via T32.-), S09 — Other and unspecified injuries of head (via T32.-), S10 — Superficial injury of neck (via T32.-), S10-S19 — Injuries to the neck (S10-S19) (via T32.-), S11 — Open wound of neck (via T32.-), S12 — Fracture of cervical vertebra and other parts of neck (via T32.-), S13 — Dislocation and sprain of joints and ligaments at neck level (via T32.-), S14 — Injury of nerves and spinal cord at neck level (via T32.-), S15 — Injury of blood vessels at neck level (via T32.-), S16 — Injury of muscle, fascia and tendon at neck level (via T32.-), S17 — Crushing injury of neck (via T32.-), +99 more.

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

MS-DRG Grouper Relationships (FY2026)

MCC — Major 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 110 clinically related codes on its CMS exclusion list.

Potential MS-DRG participation — not a DRG assignment.

Named in the grouper logic of 1 MS-DRG: DRG 927 (MDC 22).

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

Clinical classification (AHRQ CCSR):INJ019 — Burn and corrosion, 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 MCC — 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.

T32.76 — Corrosions involving 70-79% of body surface with 60-69% third degree corrosion, T32.77 — Corrosions involving 70-79% of body surface with 70-79% third degree corrosion, T32.80 — Corrosions involving 80-89% of body surface with 0% to 9% third degree corrosion, T32.81 — Corrosions involving 80-89% of body surface with 10-19% third degree corrosion, T32.82 — Corrosions involving 80-89% of body surface with 20-29% third degree corrosion, T32.83 — Corrosions involving 80-89% of body surface with 30-39% third degree corrosion, T32.84 — Corrosions involving 80-89% of body surface with 40-49% third degree corrosion, T32.85 — Corrosions involving 80-89% of body surface with 50-59% third degree corrosion, T32.86 — Corrosions involving 80-89% of body surface with 60-69% third degree corrosion, T32.87 — Corrosions involving 80-89% of body surface with 70-79% third degree corrosion, T32.88 — Corrosions involving 80-89% of body surface with 80-89% third degree corrosion, T32.90 — Corrosions involving 90% or more of body surface with 0% to 9% third degree corrosion, T32.91 — Corrosions involving 90% or more of body surface with 10-19% third degree corrosion, T32.92 — Corrosions involving 90% or more of body surface with 20-29% third degree corrosion, T32.93 — Corrosions involving 90% or more of body surface with 30-39% third degree corrosion, T32.94 — Corrosions involving 90% or more of body surface with 40-49% third degree corrosion, T32.95 — Corrosions involving 90% or more of body surface with 50-59% third degree corrosion, T32.96 — Corrosions involving 90% or more of body surface with 60-69% third degree corrosion, T32.97 — Corrosions involving 90% or more of body surface with 70-79% third degree corrosion, T32.98 — Corrosions involving 90% or more of body surface with 80-89% third degree corrosion, +89 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Severe Skin Burn) for risk-adjusted payment.

T32.74 — Corrosions involving 70-79% of body surface with 40-49% third degree corrosion, T32.75 — Corrosions involving 70-79% of body surface with 50-59% third degree corrosion, T32.76 — Corrosions involving 70-79% of body surface with 60-69% third degree corrosion, T32.77 — Corrosions involving 70-79% of body surface with 70-79% third degree corrosion, T32.81 — Corrosions involving 80-89% of body surface with 10-19% third degree corrosion, T32.82 — Corrosions involving 80-89% of body surface with 20-29% third degree corrosion, T32.83 — Corrosions involving 80-89% of body surface with 30-39% third degree corrosion, T32.84 — Corrosions involving 80-89% of body surface with 40-49% third degree corrosion, T32.85 — Corrosions involving 80-89% of body surface with 50-59% third degree corrosion, T32.86 — Corrosions involving 80-89% of body surface with 60-69% third degree corrosion, T32.87 — Corrosions involving 80-89% of body surface with 70-79% third degree corrosion, T32.88 — Corrosions involving 80-89% of body surface with 80-89% third degree corrosion, T32.91 — Corrosions involving 90% or more of body surface with 10-19% third degree corrosion, T32.92 — Corrosions involving 90% or more of body surface with 20-29% third degree corrosion, T32.93 — Corrosions involving 90% or more of body surface with 30-39% third degree corrosion, T32.94 — Corrosions involving 90% or more of body surface with 40-49% third degree corrosion, T32.95 — Corrosions involving 90% or more of body surface with 50-59% third degree corrosion, T32.96 — Corrosions involving 90% or more of body surface with 60-69% third degree corrosion, T32.97 — Corrosions involving 90% or more of body surface with 70-79% third degree corrosion, T32.98 — Corrosions involving 90% or more of body surface with 80-89% third degree corrosion, +69 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Burn and corrosion, initial encounter).

+935 more

Contextual Map

Every relationship of T32.99 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 T32.99 with these 9 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes (119)

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 385 — Severe Skin Burn [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

  • MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
  • DRG 927 — EXTENSIVE BURNS OR FULL THICKNESS BURNS WITH MV >96 HOURS WITH SKIN GRAFT[MS-DRG]: “EXTENSIVE BURNS OR FULL THICKNESS BURNS WITH MV >96 HOURS WITH SKIN GRAFT (MDC 22)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

  • MDC 22 — Burns[MDC crossing]: “Burns — 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. 377 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal), extent (percentage of body surface), 90 percent or more (0-9 percent third degree), with, 90-99 percent third degree[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal), unspecified site with extent of body surface involved specified, 90 percent or more (0-9 percent third degree), with, 90-99 percent third degree[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

Change history

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

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
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Corrosions involving 90% or more of body surface with 90% or more third degree corrosion

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 T32.99 in its code family, with their registry titles.

View all codes in the T32 family