T78.2 vs T78.2XXA
T78.2 (Anaphylactic shock, unspecified) compared with T78.2XXA (Anaphylactic shock, unspecified, initial encounter), from the official CMS tabular data.
Summary
These codes represent different levels of the same hierarchy: T78.2 is the non-billable header that contains T78.2XXA, so only T78.2XXA (or a sibling) is reported.
Registry fact- What is different?
Title wording and billing status.T78.2XXA’s title adds “initial encounter” to the wording the two share (“Anaphylactic shock, unspecified”). T78.2 is a non-billable header; T78.2XXA is billable.
Registry fact
- Can these codes be reported together?
Not as a pair.T78.2 is the non-billable header that contains T78.2XXA. A header is not reported on a claim, so the choice is T78.2XXA or a sibling that matches the documentation.
Registry fact
- Is there an Excludes1 relationship?
None.Neither entry carries an Excludes1 note that names the other code. T78.2 carries 3 Excludes1 notes and T78.2XXA carries 3 Excludes1 notes covering other codes; the side-by-side table quotes them.
Official rule
- Is there an Excludes2 relationship?
None.Neither entry carries an Excludes2 note that names the other code. T78.2 carries 1 Excludes2 note and T78.2XXA carries 1 Excludes2 note covering other codes; the side-by-side table quotes them.
Official rule
- Is one more specific?
Yes.T78.2XXA is a subdivision of T78.2 in the tabular hierarchy, so it is the more specific of the two.
Registry fact
- Is one a parent or header code?
Yes.T78.2 is the non-billable header that contains T78.2XXA. A header stands for the whole family beneath it and is not reported on a claim.
Registry fact
- Are there sequencing instructions?
None.Neither entry carries a Code First or Use Additional Code note that names the other.
Official rule
- Are there other coding relationships?
None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.
MedCoder-derived
Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels
Can these codes be reported together?
Not as a pair — T78.2 is not reportable. T78.2 is the non-billable category that contains T78.2XXA.
A header stands for the whole family of codes beneath it and is not reported on a claim, so the choice is T78.2XXA or a sibling that matches the documentation. No Excludes1/Excludes2 relationship exists between these codes in the official tabular list.
Official guidance behind these answers
Section I.B.2 — Level of Detail in Coding · applies to: T78.2 and T78.2XXA
Diagnosis codes are to be used and reported at their highest number of characters available and to the highest level of specificity documented in the medical record. ICD-10-CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 characters. Codes with three characters are included in ICD-10-CM as the heading of a category of codes that may be further subdivided by the use of fourth and/or fifth characters and/or sixth characters, which provide greater detail. A three-character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.
ICD-10-CM Official Guidelines FY2026
Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum
Side by side
| T78.2Anaphylactic shock, unspecified | T78.2XXAAnaphylactic shock, unspecified, initial encounter | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Anaphylactic shock, unspecified is a non-billable ICD-10-CM category code (T78.2). | Anaphylactic shock, unspecified, initial encounter is a billable ICD-10-CM diagnosis code (T78.2XXA). |
| 7th character | The appropriate 7th character is to be added to each code from category T78 | The appropriate 7th character is to be added to each code from category T78 |
| Includes | Allergic shock Anaphylactic reaction Anaphylaxis | Allergic shock Anaphylactic reaction Anaphylaxis |
| Excludes1 | anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6) anaphylactic reaction or shock due to adverse food reaction (T78.0-) anaphylactic reaction or shock due to serum (T80.5-) | anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6) anaphylactic reaction or shock due to adverse food reaction (T78.0-) anaphylactic reaction or shock due to serum (T80.5-) |
| Excludes2 | complications of surgical and medical care NEC (T80-T88) | complications of surgical and medical care NEC (T80-T88) |
| 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-) | , 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 are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.
Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources