2027 ICD-10-CM Diagnosis Code T79.4XXATraumatic shock, initial encounter
ICD-10-CM Codes›S00–T88›T79›T79
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 2
- 7th Character A — Initial Encounter
- Not Chronic
T79.4XXA is a billable ICD-10-CM diagnosis code for traumatic shock, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793, 922 through 923, 963 through 965. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. This status applies only when the patient is discharged alive, and not when the principal diagnosis is one of 64 closely related codes. Coders also document this condition as burn shock. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified injury.
For Medicare Advantage risk adjustment, T79.4XXA maps to CMS-HCC Category 2 (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock) under the V28 model, adding a risk factor of about 0.500 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
T79.4XXA maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Burn shock
- Traumatic shock
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Certain early complications of trauma, not elsewhere classified (T79). 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 T79.4XXA: its own notes plus those printed at T79.4, T79, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- anaphylactic shock due to adverse food reaction (T78.0-)
- anaphylactic shock due to correct medicinal substance properly administered (T88.6)
- anaphylactic shock due to serum (T80.5-)
- anaphylactic shock NOS (T78.2)
- electric shock (T75.4)
- nontraumatic shock NEC (R57.-)
- obstetric shock (O75.1)
- postprocedural shock (T81.1-)
- septic shock (R65.21)
- shock complicating abortion or ectopic or molar pregnancy (O00-O07, O08.3)
- shock due to anesthesia (T88.2)
- shock due to lightning (T75.01)
- shock NOS (R57.9)
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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- 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.
- The appropriate 7th character is to be added to each code from category T79
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name T79.4XXA, its category, or a range that includes it.
Excludes1 3
These codes carry an Excludes1 note naming T79.4XXA: they are not reported together with it, unless the two conditions are unrelated.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Shock, Traumatic
shock produced as a result of trauma.
Patient EducationClinical
Shock
Shock happens when not enough blood and oxygen can get to your organs and tissues. It causes very low blood pressure and may be life-threatening. It often happens along with a serious injury.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T79.4XXA to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T79.4XXAOverview
What is the ICD-10 code for traumatic shock, initial encounter?
The ICD-10-CM code for traumatic shock, initial encounter is T79.4XXA (sometimes written as T794XXA). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is T79.4XXA (Traumatic shock) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report traumatic shock, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in T79.4XXA mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for traumatic shock, such as an emergency visit or first evaluation.
What MS-DRG does T79.4XXA group to?
When traumatic shock, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 964, 923, 965, 922, 963, with relative weights from 0.9980 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T79.4XXA a CC or MCC?
CMS lists T79.4XXA as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It carries this status only when the patient is discharged alive. It does not count when the principal diagnosis is one of the 64 closely related codes in its exclusion list.
What HCC is T79.4XXA?
T79.4XXA (traumatic shock, initial encounter) maps to CMS-HCC Category 2 (Septicemia, Sepsis, Systemic Inflammatory Response Syndrome/Shock), commonly written as HCC 2, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 173 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does T79.4XXA risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, T79.4XXA adds a risk adjustment factor of about 0.500 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.447 to 0.780 depending on the payment segment). HCC 2 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 2 category page.
