T65.851A vs Z77
T65.851A (Toxic effect of medetomidine, accidental (unintentional), initial encounter) compared with Z77 (Other contact with and (suspected) exposures hazardous to health), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. T65.851A carries an Excludes1 note covering Z77: “contact with and (suspected) exposure to toxic substances (Z77.-)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Yes, when both are documented. Z77 carries an Excludes2 note covering T65.851A: “toxic effects of substances chiefly nonmedicinal as to source (T51-T65)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Side by side
| T65.851AToxic effect of medetomidine, accidental (unintentional), initial encounter | Z77Other contact with and (suspected) exposures hazardous to health | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) | Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99) |
| Definition | — | Other contact with and (suspected) exposures hazardous to health is a non-billable ICD-10-CM category code (Z77). |
| 7th character | The appropriate 7th character is to be added to each code from category T65 | — |
| Includes | Toxic effect of medetomidine NOS | contact with and (suspected) exposures to potential hazards to health |
| Use additional code | code to identify associated manifestations, such as: bradycardia NOS (R00.1) somnolence, stupor and coma (R40.-) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources