2027 ICD-10-CM Diagnosis Code T78.2XXSAnaphylactic shock, unspecified, sequela
T78.2XXS is a billable ICD-10-CM diagnosis code for anaphylactic shock, unspecified, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Injury, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T78.2XXS is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Other and unspecified effects of external causes (T66-T78).
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Allergic reaction caused by Hevea brasiliensis latex protein
- Allergic reaction caused by hymenoptera venom
- Allergic reaction caused by insect bite and/or insect sting
- Allergic reaction to bee sting
- Allergic reaction to wasp sting
- Anaphylactic shock
- Anaphylactoid glomerulonephritis
- Anaphylaxis
- Anaphylaxis caused by Hevea brasiliensis latex protein
- Anaphylaxis caused by honey bee venom
- Anaphylaxis caused by hornet venom
- Anaphylaxis caused by hymenoptera venom
- Anaphylaxis caused by insect bite and/or insect sting
- Anaphylaxis caused by insect venom
- Anaphylaxis caused by low temperature
- Anaphylaxis caused by venom
- Anaphylaxis due to mast cell disorder
- Bee sting-induced anaphylaxis
- Drug-induced anaphylaxis
- Exercise anaphylaxis
- Food-dependent exercise-induced anaphylaxis
- Iatrogenic non-allergic anaphylaxis
- Idiopathic anaphylaxis
- Insulin adverse reaction
- Insulin-induced anaphylaxis
- Late effect of accidental injury
- Localized anaphylaxis
- Non-allergic anaphylaxis
- Non-allergic anaphylaxis caused by organic phosphorous compound
- Seminal fluid-induced anaphylaxis
- Wasp sting-induced anaphylaxis
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Adverse effects, not elsewhere classified (T78). 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 T78.2XXS: its own notes plus those printed at T78.2, T78, block T66-T78, 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.
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.-)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
- if applicable, place of occurrence, such as:
- highway rest stop (Y92.523)
- school (private) (public) (state) as the place of occurrence of the external cause (Y92.21-)
- service areas as the place of occurrence of the external cause (Y92.52-)
- single-family non-institutional (private) house as the place of occurrence of the external cause (Y92.01-)
- transport vehicle as the place of occurrence of the external cause (Y92.81-)
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 T78
- Ainitial encounter
- Dsubsequent encounter
- Ssequela this code
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name T78.2XXS, its category, or a range that includes it.
Excludes1 6
These codes carry an Excludes1 note naming T78.2XXS: they are not reported together with it, unless the two conditions are unrelated.
- R57 Shock, not elsewhere classifiedanaphylactic shock NOS (T78.2) names T78.2, which includes this code
- T75 Other and unspecified effects of other external causesadverse effects NEC (T78.-) names T78.-, which includes this code
- T79.4 Traumatic shockanaphylactic shock NOS (T78.2) names T78.2, which includes this code
- T80.5 Anaphylactic reaction due to serumallergic reaction or shock NOS (T78.2) names T78.2, which includes this code
- T80.5 Anaphylactic reaction due to serumanaphylactic reaction or shock NOS (T78.2) names T78.2, which includes this code
- T81.1 Postprocedural shockanaphylactic shock NOS (T78.2) names T78.2, which includes this code
Use Additional Code 1
These codes say to use an additional code from the note, and T78.2XXS is one of the codes named.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Anaphylactic Shock
progression of anaphylaxis into systemic shock, which is characterized by significant reduction in tissue perfusion which leads to hypoxia and hypotension, and can lead to death if untreated.
Patient EducationClinical
Anaphylaxis
Anaphylaxis is a serious allergic reaction. It can begin very quickly, and symptoms may be life-threatening. The most common causes are reactions to foods (especially peanuts), medications, and stinging insects. Other causes include exercise and exposure to latex. Sometimes no cause can be found.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T78.2XXS to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T78.2XXSOverview
What is the ICD-10 code for anaphylactic shock, unspecified, sequela?
The ICD-10-CM code for anaphylactic shock, unspecified, sequela is T78.2XXS (sometimes written as T782XXS). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is T78.2XXS (Anaphylactic shock, unspecified) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report anaphylactic shock, unspecified, sequela on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character S in T78.2XXS mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the anaphylactic shock, unspecified itself has resolved, not the original event.
What MS-DRG does T78.2XXS group to?
When anaphylactic shock, unspecified, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 923, 922, with relative weights from 0.9980 to 1.6248 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T78.2XXS exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for anaphylactic shock, unspecified, sequela on inpatient claims. The code appears in the Other and unspecified effects of external causes (T66-T78) range of the CMS exempt list.
