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S83.31XD vs T63.4

S83.31XD (Tear of articular cartilage of right knee, current, subsequent encounter) compared with T63.4 (Toxic effect of venom of other arthropods), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because S83.31XD lists T63.4 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.S83.31XD is “Tear of articular cartilage of right knee, current, subsequent encounter”; T63.4 is “Toxic effect of venom of other arthropods”. T63.4 is a non-billable header; S83.31XD is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.S83.31XD lists T63.4 under Excludes2: “insect bite or sting, venomous (T63.4)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. T63.4 carries 1 Excludes1 note covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.S83.31XD’s tabular entry: “insect bite or sting, venomous (T63.4)”. The note covers T63.4.

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.T63.4 is a non-billable header, but S83.31XD 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?

Informational

Excludes2 relationship

S83.31XD
Tear of articular cartilage of right knee, current, subsequent encounter
↔
T63.4
Toxic effect of venom of other arthropods

What we found

Yes, when both are documented.S83.31XD carries an Excludes2 note covering T63.4: “insect bite or sting, venomous (T63.4)”

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.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

S83.31XDTear of articular cartilage of right knee, current, subsequent encounterT63.4Toxic effect of venom of other arthropods
Billing statusBillableNon-billable header

Report instead: T63.411A, T63.411D, T63.411S, T63.412A, T63.412D

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)
DefinitionTear of articular cartilage of right knee, current, subsequent encounter is a billable ICD-10-CM diagnosis code (S83.31XD).Toxic effect of venom of other arthropods is a non-billable ICD-10-CM category code (T63.4).
7th characterThe appropriate 7th character is to be added to each code from category S83The appropriate 7th character is to be added to each code from category T63
Includes
avulsion of joint or ligament of knee
laceration of cartilage, joint or ligament of knee
sprain of cartilage, joint or ligament of knee
traumatic hemarthrosis of joint or ligament of knee
bite or touch of venomous animal
pricked or stuck by thorn or leaf
Excludes1—
contact with and (suspected) exposure to toxic substances (Z77.-)
Excludes2
derangement of patella (M22.0-M22.3)
injury of patellar ligament (tendon) (S76.1-)
internal derangement of knee (M23.-)
old dislocation of knee (M24.36)
pathological dislocation of knee (M24.36)
recurrent dislocation of knee (M22.0)
strain of muscle, fascia and tendon of lower leg (S86.-)
burns and corrosions (T20-T32)
frostbite (T33-T34)
injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)
insect bite or sting, venomous (T63.4)
ingestion of toxic animal or plant (T61.-, T62.-)
Use additional code—
code, if applicable, for anaphylactic shock (T78.2)
code(s):
for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)
Code also
any associated open wound
—

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 (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources