T88.6XXA ICD-10-CM Code: Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T88.6XXA in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on T88.6XXA itself; “inherited from” names the category or block whose note applies here.

7th Character Guide

"The appropriate 7th character is to be added to each code from category T88"

• 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

T88.6XXA, T88.6XXD, T88.6XXS

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.

Coder workflow for T88.6XXA

MedCoder structured workflow — derived from this code’s own official record

Before you code T88.6XXA

1. A 7th character is required in this family. Confirm the documented encounter: initial (active treatment), subsequent (healing or recovery phase), or sequela. This page’s code carries “A”. “Initial” means active treatment, not the first visit (Guidelines I.C.19.a).

   See the 7th Character Guide · Guide: 7th characters: initial, subsequent, sequela →

2. T88.6XXA’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

   Guide: Combination codes →

3. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with T88.6XXA. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support a condition named in T88.6XXA’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewT80.5, T78.0

2. Is the encounter phase documented — active treatment, healing or recovery, or a sequela?
   Yes → Assign the matching 7th character; the variant codes are in the 7th Character Guide.
   No → The code is invalid without its 7th character — query for the missing element.

Consider T88.6XXA. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Encounter type

Active treatment, healing or recovery phase, or sequela — the basis of the 7th character (Guidelines I.C.19.a).

The associated condition or complication

Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

The conditions the Use Additional Code note names

Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

• Excludes1 — check before selecting T88.6XXA(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with T88.6XXA: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareT80.5, T78.0

  See the official tabular notes · Guidelines I.A.12.a

• Excludes2 — not part of T88.6XXA(31 notes)

  Coding workflow: The conditions named in this note are not included in T88.6XXA. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareT80, T81, O74, O29, O89, O75.4

  See the official tabular notes · Guidelines I.A.12.b

• Use Additional Code — after identifying T88.6XXA(3 notes)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with T88.6XXA when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse T88.6XXA with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of T88.6XXA — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• T80.5— Excludes1 conflict (Conflict)

  Not coded here — these two are mutually exclusive.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic reaction due to serum moves the case to T80.5; the two are not reported together unless documented as unrelated.

  Full comparison: T88.6XXA vs T80.5 →

• T78.0— Excludes1 conflict (Conflict)

  Not coded here — these two are mutually exclusive.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of anaphylactic shock or reaction due to adverse food reaction moves the case to T78.0; the two are not reported together unless documented as unrelated.

  Full comparison: T88.6XXA vs T78.0 →

• T88.6XXD— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a subsequent encounter moves the case to T88.6XXD.

  Full comparison: T88.6XXA vs T88.6XXD →

• T88.6XXS— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a sequela moves the case to T88.6XXS.

  Full comparison: T88.6XXA vs T88.6XXS →

• T80— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of complication following infusion, transfusion and therapeutic injection adds T80; it is not part of this code and both may be reported when both are documented.

  Full comparison: T88.6XXA vs T80 →

• T81— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of complication following procedure NEC adds T81; it is not part of this code and both may be reported when both are documented.

  Full comparison: T88.6XXA vs T81 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

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. 3 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
3. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
4. 31 Excludes2 entries — 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

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name T88.6XXA 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 2 Excludes2 notes: T78 — Adverse effects, not elsewhere classified (via T88.-), T79 — Certain early complications of trauma, not elsewhere classified (via T88.-).

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

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

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 15 clinically related codes on its CMS exclusion list.

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):INJ037 — Complication of other surgical or medical care, injury, initial encounter (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, T78.09XA — Anaphylactic reaction due to other food products, initial encounter

Same injury, other encounter phase

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

T88.6XXD — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, subsequent encounterCompare T88.6XXA vs T88.6XXD →, T88.6XXS — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, sequelaCompare T88.6XXA vs T88.6XXS →

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Complication of other surgical or medical care, injury, initial encounter).

T87.50 — Necrosis of amputation stump, unspecified extremity, T87.51 — Necrosis of amputation stump, right upper extremity, T87.52 — Necrosis of amputation stump, left upper extremity, T87.53 — Necrosis of amputation stump, right lower extremity, T87.54 — Necrosis of amputation stump, left lower extremity, T87.81 — Dehiscence of amputation stump, T87.89 — Other complications of amputation stump, T87.9 — Unspecified complications of amputation stump, T88.0XXA — Infection following immunization, initial encounter, T88.1XXA — Other complications following immunization, not elsewhere classified, initial encounter, T88.2XXA — Shock due to anesthesia, initial encounter, T88.3XXA — Malignant hyperthermia due to anesthesia, initial encounter, T88.4XXA — Failed or difficult intubation, initial encounter, T88.51XA — Hypothermia following anesthesia, initial encounter, T88.52XA — Failed moderate sedation during procedure, initial encounter, T88.53XA — Unintended awareness under general anesthesia during procedure, initial encounter, T88.59XA — Other complications of anesthesia, initial encounter, T88.7XXA — Unspecified adverse effect of drug or medicament, initial encounter, T88.8XXA — Other specified complications of surgical and medical care, not elsewhere classified, initial encounter, T88.9XXA — Complication of surgical and medical care, unspecified, initial encounter, +230 more

Contextual Map

Every relationship of T88.6XXA 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.

Run T88.6XXA with these 2 related codes in Claim Check

Hierarchy

• S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T80-T88 — Complications of surgical and medical care, not elsewhere classified[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes

• T78 — Adverse effects, not elsewhere classified[Excludes2](via T88.-): “complications of surgical and medical care NEC (T80-T88)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• T79 — Certain early complications of trauma, not elsewhere classified[Excludes2](via T88.-): “complications occurring during or following medical procedures (T80-T88)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• INJ037 — Complication of other surgical or medical care, injury, initial encounter[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 915 — ALLERGIC REACTIONS WITH MCC[MS-DRG]: “ALLERGIC REACTIONS WITH MCC (MDC 21)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 916 — ALLERGIC REACTIONS WITHOUT MCC[MS-DRG]: “ALLERGIC REACTIONS WITHOUT MCC (MDC 21)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

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.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

• T88 — Other complications of surgical and medical care, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.3 — Malignant hyperthermia due to anesthesia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.3XXA — Malignant hyperthermia due to anesthesia, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.3XXD — Malignant hyperthermia due to anesthesia, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.3XXS — Malignant hyperthermia due to anesthesia, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.4 — Failed or difficult intubation[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.4XXA — Failed or difficult intubation, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• T88.4XXD — Failed or difficult intubation, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T88.6XXA in its code family, with their registry titles.

• T88.59 — Other complications of anesthesia
• T88.59XA — Other complications of anesthesia, initial encounter
• T88.59XD — Other complications of anesthesia, subsequent encounter
• T88.59XS — Other complications of anesthesia, sequela
• T88.6 — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered
• T88.6XXD — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, subsequent encounter
• T88.6XXS — Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, sequela
• T88.7 — Unspecified adverse effect of drug or medicament
• T88.7XXA — Unspecified adverse effect of drug or medicament, initial encounter
• T88.7XXD — Unspecified adverse effect of drug or medicament, subsequent encounter

View all codes in the T88 family