T65 ICD-10-CM Code: Toxic effect of other and unspecified substances
T65 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Injury, poisoning and certain other consequences of external causes (S00-T88) / Toxic effects of substances chiefly nonmedicinal as to source (T51-T65)
T65
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceToxic effect of other and unspecified substances
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for T65. Check the code and parent instructions in the Code Book.
Excludes 2
Official- birth trauma (P10-P15)Inherited from S00-T88
- obstetric trauma (O70-O71)Inherited from S00-T88
Related Codes
Includes
OfficialNo Includes notes are included in this display for T65. Check the code and parent instructions in the Code Book.
Excludes 1
Official- contact with and (suspected) exposure to toxic substances (Z77.-)Inherited from T51-T65
Code First
OfficialNo Code First sequencing instructions are included in this display for T65. Check the code and parent instructions in the Code Book.
Use Additional
Official- code to identify any retained foreign body, if applicable (Z18.-)Inherited from S00-T88, T51-T65
- code(s):Inherited from S00-T88, T51-T65
- for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)Inherited from S00-T88, T51-T65
- personal history of foreign body fully removed (Z87.821)Inherited from S00-T88, T51-T65
- to identify any retained foreign body, if applicable (Z18.-)Inherited from S00-T88, T51-T65
Code Also
OfficialNo Code Also instructions are included in this display for T65. Check the code and parent instructions in the Code Book.
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
- Code
- T65
- Description
- Toxic effect of other and unspecified substances
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- No
- Payment year
- 2026
Coder workflow notes
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What This Code Means
T65 is the ICD-10-CM diagnosis code for toxic effect of other and unspecified substances. T65 sits in the ICD-10-CM chapter for injury, poisoning and certain other consequences of external causes (s00-t88), within the section covering toxic effects of substances chiefly nonmedicinal as to source (t51-t65).
Header codes like T65 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for T65 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.