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T78.09XA ICD-10-CM Code: Anaphylactic reaction due to other food products, initial encounter

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

Coding at a Glance

7th character
Required — see the character table on this page
Tabular directives
1 Excludes2 · 6 code-also instructions

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 v43.0, Appendix B.

  • MS-DRG 915 — ALLERGIC REACTIONS WITH MCC (MDC 21)
  • MS-DRG 916 — ALLERGIC REACTIONS WITHOUT MCC (MDC 21)

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.

Code Overview

Anaphylactic reaction due to other food products, initial encounter is a billable ICD-10-CM diagnosis code (T78.09XA).

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

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for T78.09XA in the official ICD-10-CM tabular list.

Notes without a marker are published on T78.09XA itself; “inherited from” names the category or block whose note applies here.

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Source: inherited from T78

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, 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-)

Source: inherited from T66-T78

7th Character Guide

"The appropriate 7th character is to be added to each code from category T78"

  • 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

T78.09XA, T78.09XD, T78.09XS

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.

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Anaphylactic reaction due to other food products, initial encounter

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.

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. 6 Code Also notes — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 1 Excludes2 entry — 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

  • 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

Other codes that name T78.09XA 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 8 Excludes1 notes across 2 chapters: R57 — Shock, not elsewhere classified (via T78.0.-), T61 — Toxic effect of noxious substances eaten as seafood (via T78.0.-), T62 — Toxic effect of other noxious substances eaten as food (via T78.0.-), T75 — Other and unspecified effects of other external causes (via T78.-), T78.1 — Other adverse food reactions, not elsewhere classified (via T78.0.-), T78.2 — Anaphylactic shock, unspecified (via T78.0.-), T79.4 — Traumatic shock (via T78.0.-), T88.6 — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered (via T78.0.-).

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

Referenced by 1 Excludes2 note: L27 — Dermatitis due to substances taken internally (via T78.-).

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

MS-DRG Grouper Relationships (FY2026)

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 14 clinically related codes on its CMS exclusion list.

Potential MS-DRG participation — not a DRG assignment.

Named in the grouper logic of 2 MS-DRGs: DRG 915 (MDC 21), DRG 916 (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):INJ031 — Allergic reactions (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.

T78.00XA — Anaphylactic reaction due to unspecified food, initial encounter, T78.01XA — Anaphylactic reaction due to peanuts, initial encounter, T78.02XA — Anaphylactic reaction due to shellfish (crustaceans), initial encounter, T78.03XA — Anaphylactic reaction due to other fish, initial encounter, T78.04XA — Anaphylactic reaction due to fruits and vegetables, initial encounter, T78.05XA — Anaphylactic reaction due to tree nuts and seeds, initial encounter, T78.06XA — Anaphylactic reaction due to food additives, initial encounter, T78.070A — Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, initial encounter, T78.071A — Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, initial encounter, T78.079A — Anaphylactic reaction due to milk and dairy products, unspecified, initial encounter, T78.080A — Anaphylactic reaction due to egg with tolerance to baked egg, initial encounter, T78.081A — Anaphylactic reaction due to egg with reactivity to baked egg, initial encounter, T78.089A — Anaphylactic reaction due to eggs, unspecified, initial encounter

Same injury, other encounter phase

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

T78.09XD — Anaphylactic reaction due to other food products, subsequent encounterCompare T78.09XA vs T78.09XD →, T78.09XS — Anaphylactic reaction due to other food products, sequelaCompare T78.09XA vs T78.09XS →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Allergic reactions).

T78.03XA — Anaphylactic reaction due to other fish, initial encounter, T78.04XA — Anaphylactic reaction due to fruits and vegetables, initial encounter, T78.05XA — Anaphylactic reaction due to tree nuts and seeds, initial encounter, T78.06XA — Anaphylactic reaction due to food additives, initial encounter, T78.070A — Anaphylactic reaction due to milk and dairy products with tolerance to baked milk, initial encounter, T78.071A — Anaphylactic reaction due to milk and dairy products with reactivity to baked milk, initial encounter, T78.079A — Anaphylactic reaction due to milk and dairy products, unspecified, initial encounter, T78.080A — Anaphylactic reaction due to egg with tolerance to baked egg, initial encounter, T78.081A — Anaphylactic reaction due to egg with reactivity to baked egg, initial encounter, T78.089A — Anaphylactic reaction due to eggs, unspecified, initial encounter, T78.110A — Other adverse food reactions due to milk and dairy products with tolerance to baked milk, initial encounter, T78.111A — Other adverse food reaction due to milk and dairy products with reactivity to baked milk, initial encounter, T78.119A — Other adverse food reaction due to milk and dairy products with baked milk tolerance/reactivity, unspecified, initial encounter, T78.120A — Other adverse food reaction due to egg with tolerance to baked egg, initial encounter, T78.121A — Other adverse food reaction due to egg with reactivity to baked egg, initial encounter, T78.129A — Other adverse food reaction due to egg with baked egg tolerance/reactivity, unspecified, initial encounter, T78.19XA — Other adverse food reactions, not elsewhere classified, initial encounter, T78.2XXA — Anaphylactic shock, unspecified, initial encounter, T78.3XXA — Angioneurotic edema, initial encounter, T78.40XA — Allergy, unspecified, initial encounter, +93 more

Contextual Map

Every relationship of T78.09XA 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.

Hierarchy

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Clinical classification (CCSR)

MS-DRG Grouper

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.”

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]

Frequently Asked Questions (FAQ) & Clinical Guidance

Does T78.09XA require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T78.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T78.09XA in its code family, with their registry titles.

View all codes in the T78 family