T79.4XXA ICD-10-CM Code: Traumatic shock, initial encounter

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T79.4XXA 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 T79.4XXA 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 T79"

• 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

T79.4XXA, T79.4XXD, T79.4XXS

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 T79.4XXA

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

Before you code T79.4XXA

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. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with T79.4XXA. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support a condition named in T79.4XXA’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewT78.0, T88.6, T80.5, T78.2, T75.4, R57

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 T79.4XXA. 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).

Encounter type

Active treatment, healing or recovery phase, or sequela — the basis of the 7th character (Guidelines I.C.19.a).

Official instructions as workflow

• Excludes1 — check before selecting T79.4XXA(13 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with T79.4XXA: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareT78.0, T88.6, T80.5, T78.2, T75.4, R57

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

• Excludes2 — not part of T79.4XXA(4 notes)

  Coding workflow: The conditions named in this note are not included in T79.4XXA. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareJ80, P22.0

  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 T79.4XXA with…

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

The codes most likely to be picked instead of T79.4XXA — 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.

• T78.0— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic shock due to adverse food reaction moves the case to T78.0; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs T78.0 →

• T88.6— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic shock due to correct medicinal substance properly administered moves the case to T88.6; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs T88.6 →

• T80.5— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic shock due to serum moves the case to T80.5; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs T80.5 →

• T78.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic shock NOS moves the case to T78.2; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs T78.2 →

• T75.4— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of electric shock moves the case to T75.4; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs T75.4 →

• R57— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of nontraumatic shock NEC moves the case to R57; the two are not reported together unless documented as unrelated.

  Full comparison: T79.4XXA vs R57 →

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.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
2. 13 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
3. 4 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

• MCC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier; counts only for patients discharged alive.

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: 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 62 clinically related codes on its CMS exclusion list. Counts only for patients discharged alive; otherwise treated as a non-CC.

Named in the grouper logic of 7 MS-DRGs: DRG 791 (MDC 15), DRG 793 (MDC 15), DRG 922 (MDC 21), DRG 923 (MDC 21), DRG 963 (MDC 24), DRG 964 (MDC 24), DRG 965 (MDC 24).

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

Clinical classification (AHRQ CCSR):INJ026 — Other specified injury (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. Counts only for patients discharged alive. 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.

M96.89 — Other intraoperative and postprocedural complications and disorders of the musculoskeletal system, N98.1 — Hyperstimulation of ovaries, N98.2 — Complications of attempted introduction of fertilized ovum following in vitro fertilization, N98.3 — Complications of attempted introduction of embryo in embryo transfer, N98.8 — Other complications associated with artificial fertilization, N98.9 — Complication associated with artificial fertilization, unspecified, T07.XXXA — Unspecified multiple injuries, initial encounter, T14.8XXA — Other injury of unspecified body region, initial encounter, T14.90XA — Injury, unspecified, initial encounter, T14.91XA — Suicide attempt, initial encounter, T79.8XXA — Other early complications of trauma, initial encounter, T79.9XXA — Unspecified early complication of trauma, initial encounter, T79.A0XA — Compartment syndrome, unspecified, initial encounter, T79.A11A — Traumatic compartment syndrome of right upper extremity, initial encounter, T79.A12A — Traumatic compartment syndrome of left upper extremity, initial encounter, T79.A19A — Traumatic compartment syndrome of unspecified upper extremity, initial encounter, T79.A21A — Traumatic compartment syndrome of right lower extremity, initial encounter, T79.A22A — Traumatic compartment syndrome of left lower extremity, initial encounter, T79.A29A — Traumatic compartment syndrome of unspecified lower extremity, initial encounter, T79.A3XA — Traumatic compartment syndrome of abdomen, initial encounter, +41 more

Same injury, other encounter phase

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

T79.4XXD — Traumatic shock, subsequent encounterCompare T79.4XXA vs T79.4XXD →, T79.4XXS — Traumatic shock, sequelaCompare T79.4XXA vs T79.4XXS →

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock) for risk-adjusted payment.

B00.7 — Disseminated herpesviral disease, B37.7 — Candidal sepsis, M35.81 — Multisystem inflammatory syndrome, P02.70 — Newborn affected by fetal inflammatory response syndrome, P36.0 — Sepsis of newborn due to streptococcus, group B, P36.10 — Sepsis of newborn due to unspecified streptococci, P36.19 — Sepsis of newborn due to other streptococci, P36.2 — Sepsis of newborn due to Staphylococcus aureus, P36.30 — Sepsis of newborn due to unspecified staphylococci, P36.39 — Sepsis of newborn due to other staphylococci, P36.4 — Sepsis of newborn due to Escherichia coli, P36.5 — Sepsis of newborn due to anaerobes, P36.8 — Other bacterial sepsis of newborn, P36.9 — Bacterial sepsis of newborn, unspecified, R57.1 — Hypovolemic shock, R57.8 — Other shock, R65.10 — Systemic inflammatory response syndrome (SIRS) of non-infectious origin without acute organ dysfunction, R65.11 — Systemic inflammatory response syndrome (SIRS) of non-infectious origin with acute organ dysfunction, R65.20 — Severe sepsis without septic shock, R65.21 — Severe sepsis with septic shock, +31 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other specified injury).

S89.82XA — Other specified injuries of left lower leg, initial encounter, S99.811A — Other specified injuries of right ankle, initial encounter, S99.812A — Other specified injuries of left ankle, initial encounter, S99.819A — Other specified injuries of unspecified ankle, initial encounter, S99.821A — Other specified injuries of right foot, initial encounter, S99.822A — Other specified injuries of left foot, initial encounter, S99.829A — Other specified injuries of unspecified foot, initial encounter, T79.0XXA — Air embolism (traumatic), initial encounter, T79.1XXA — Fat embolism (traumatic), initial encounter, T79.2XXA — Traumatic secondary and recurrent hemorrhage and seroma, initial encounter, T79.5XXA — Traumatic anuria, initial encounter, T79.6XXA — Traumatic ischemia of muscle, initial encounter, T79.7XXA — Traumatic subcutaneous emphysema, initial encounter, T79.8XXA — Other early complications of trauma, initial encounter, T79.9XXA — Unspecified early complication of trauma, initial encounter, T79.A0XA — Compartment syndrome, unspecified, initial encounter, T79.A11A — Traumatic compartment syndrome of right upper extremity, initial encounter, T79.A12A — Traumatic compartment syndrome of left upper extremity, initial encounter, T79.A19A — Traumatic compartment syndrome of unspecified upper extremity, initial encounter, T79.A21A — Traumatic compartment syndrome of right lower extremity, initial encounter, +48 more

Contextual Map

Every relationship of T79.4XXA 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.

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
• T79-T79 — Certain early complications of trauma[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• INJ026 — Other specified injury[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 2 — Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock [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 791 — PREMATURITY WITH MAJOR PROBLEMS[MS-DRG]: “PREMATURITY WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS[MS-DRG]: “FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)”— CMS MS-DRG Definitions Manual (Appendix B) · 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
• DRG 963 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC[MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC (MDC 24)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 964 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC[MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC (MDC 24)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 965 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC[MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC (MDC 24)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 15 — Newborns and Other Neonates with Conditions Originating in Perinatal Period[MDC crossing]: “Newborns and Other Neonates with Conditions Originating in Perinatal Period — 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.”— CMS MS-DRG Definitions Manual · FY2026
• 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)

• T79 — Certain early complications of trauma, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.0 — Air embolism (traumatic)[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.0XXA — Air embolism (traumatic), initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.0XXD — Air embolism (traumatic), subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.0XXS — Air embolism (traumatic), sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.1 — Fat embolism (traumatic)[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.1XXA — Fat embolism (traumatic), initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T79.1XXD — Fat embolism (traumatic), subsequent encounter[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

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T79.4XXA in its code family, with their registry titles.

• T79.2 — Traumatic secondary and recurrent hemorrhage and seroma
• T79.2XXA — Traumatic secondary and recurrent hemorrhage and seroma, initial encounter
• T79.2XXD — Traumatic secondary and recurrent hemorrhage and seroma, subsequent encounter
• T79.2XXS — Traumatic secondary and recurrent hemorrhage and seroma, sequela
• T79.4 — Traumatic shock
• T79.4XXD — Traumatic shock, subsequent encounter
• T79.4XXS — Traumatic shock, sequela
• T79.5 — Traumatic anuria
• T79.5XXA — Traumatic anuria, initial encounter
• T79.5XXD — Traumatic anuria, subsequent encounter

View all codes in the T79 family