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T80.5 vs T88.6XXA

T80.5 (Anaphylactic reaction due to serum) compared with T88.6XXA (Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter), from the official CMS tabular data.

Summary

These codes should not be reported together because T80.5’s tabular entry lists T88.6XXA under Excludes1.

Official rule
What is different?

Title wording and billing status.The titles share “Anaphylactic reaction due to”; T80.5 says “serum” where T88.6XXA says “adverse effect of correct drug or medicament properly administered, initial encounter”. T80.5 is a non-billable header; T88.6XXA is billable.

Registry fact

Can these codes be reported together?

No.T80.5’s entry carries an Excludes1 note covering T88.6XXA: “anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.T80.5’s tabular entry: “anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6)”. The note covers T88.6XXA.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.T88.6XXA’s tabular entry: “complication following infusion, transfusion and therapeutic injection (T80.-)”. The note covers T80.5.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.T80.5 is a non-billable header, but T88.6XXA is not one of its subdivisions.

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?

Conflict

Excludes1 conflict

T80.5
Anaphylactic reaction due to serum
↔
T88.6XXA
Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter

What we found

No — do not report together.T80.5 carries an Excludes1 note covering T88.6XXA: “anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Informational

Excludes2 relationship

T88.6XXA
Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter
↔
T80.5
Anaphylactic reaction due to serum

What we found

Yes, when both are documented.T88.6XXA carries an Excludes2 note covering T80.5: “complication following infusion, transfusion and therapeutic injection (T80.-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    ICD-10-CM Official Guidelines FY2026

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    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

T80.5Anaphylactic reaction due to serumT88.6XXAAnaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter
Billing statusNon-billable header

Report instead: T80.51XA, T80.51XD, T80.51XS, T80.52XA, T80.52XD

Billable
ClassificationS00-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)
DefinitionAnaphylactic reaction due to serum is a non-billable ICD-10-CM category code (T80.5).Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter is a billable ICD-10-CM diagnosis code (T88.6XXA).
7th characterThe appropriate 7th character is to be added to each code from category T80The appropriate 7th character is to be added to each code from category T88
Includes
complications following perfusion
Allergic shock due to serum
Anaphylactic shock due to serum
Anaphylactoid reaction due to serum
Anaphylactic shock due to adverse effect of correct drug or medicament properly administered
Anaphylactoid reaction NOS
Excludes1
ABO incompatibility reaction due to transfusion of blood or blood products (T80.3-)
allergic reaction or shock NOS (T78.2)
anaphylactic reaction or shock NOS (T78.2)
anaphylactic reaction or shock due to adverse effect of correct medicinal substance properly administered (T88.6)
other serum reaction (T80.6-)
anaphylactic reaction due to serum (T80.5-)
anaphylactic shock or reaction due to adverse food reaction (T78.0-)
Excludes2
bone marrow transplant rejection (T86.01)
febrile nonhemolytic transfusion reaction (R50.84)
fluid overload due to transfusion (E87.71)
posttransfusion purpura (D69.51)
transfusion associated circulatory overload (TACO) (E87.71)
transfusion (red blood cell) associated hemochromatosis (E83.111)
transfusion related acute lung injury (TRALI) (J95.84)
any encounters with medical care for postprocedural conditions in which no complications are present, such as:
artificial opening status (Z93.-)
closure of external stoma (Z43.-)
fitting and adjustment of external prosthetic device (Z44.-)
burns and corrosions from local applications and irradiation (T20-T32)
complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
mechanical complication of respirator [ventilator] (J95.850)
poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
postprocedural fever (R50.82)
specified complications classified elsewhere, such as:
cerebrospinal fluid leak from spinal puncture (G97.0)
colostomy malfunction (K94.0-)
disorders of fluid and electrolyte imbalance (E86-E87)
functional disturbances following cardiac surgery (I97.0-I97.1)
intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
ostomy complications (J95.0-, K94.-, N99.5-)
postgastric surgery syndromes (K91.1)
postlaminectomy syndrome NEC (M96.1)
postmastectomy lymphedema syndrome (I97.2)
postsurgical blind-loop syndrome (K91.2)
ventilator associated pneumonia (J95.851)
complication following infusion, transfusion and therapeutic injection (T80.-)
complication following procedure NEC (T81.-)
complications of anesthesia in labor and delivery (O74.-)
complications of anesthesia in pregnancy (O29.-)
complications of anesthesia in puerperium (O89.-)
complications of devices, implants and grafts (T82-T85)
complications of obstetric surgery and procedure (O75.4)
dermatitis due to drugs and medicaments (L23.3, L24.4, L25.1, L27.0-L27.1)
poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4)
specified complications classified elsewhere
any encounters with medical care for postprocedural conditions in which no complications are present, such as:
artificial opening status (Z93.-)
closure of external stoma (Z43.-)
fitting and adjustment of external prosthetic device (Z44.-)
burns and corrosions from local applications and irradiation (T20-T32)
complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
mechanical complication of respirator [ventilator] (J95.850)
poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
postprocedural fever (R50.82)
specified complications classified elsewhere, such as:
cerebrospinal fluid leak from spinal puncture (G97.0)
colostomy malfunction (K94.0-)
disorders of fluid and electrolyte imbalance (E86-E87)
functional disturbances following cardiac surgery (I97.0-I97.1)
intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
ostomy complications (J95.0-, K94.-, N99.5-)
postgastric surgery syndromes (K91.1)
postlaminectomy syndrome NEC (M96.1)
postmastectomy lymphedema syndrome (I97.2)
postsurgical blind-loop syndrome (K91.2)
ventilator associated pneumonia (J95.851)
Use additional code
code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
code(s) to identify the specified condition resulting from the complication
code to identify devices involved and details of circumstances (Y62-Y82)
code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
code(s) to identify the specified condition resulting from the complication
code to identify devices involved and details of circumstances (Y62-Y82)

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.

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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