Is ICD-10-CM code T65.851S billable?

Yes, T65.851S (Toxic effect of medetomidine, accidental (unintentional), sequela) is a billable ICD-10-CM diagnosis code, valid for reimbursement on HIPAA-covered transactions for FY2027.

Is T65.851S exempt from POA reporting?

Yes, T65.851S is on the CMS list of ICD-10-CM codes exempt from Present On Admission (POA) reporting for FY2027. Inpatient claims do not require a POA indicator for this code.

What chapter does ICD-10-CM code T65.851S belong to?

T65.851S belongs to Chapter 19 of the ICD-10-CM tabular list: S00–T88 (Injury, Poisoning and Certain Other Consequences of External Causes).

Is T65.851S a new ICD-10-CM code for 2027?

Yes, T65.851S was added or revised in the FY2027 ICD-10-CM update, effective October 1, 2026, as published by the Centers for Medicare and Medicaid Services (CMS).

T65.851SBillable, valid for claims from October 1, 2026New for FY2027

Toxic effect of medetomidine, accidental (unintentional), sequela

Under T65.851 Toxic effect of medetomidine, accidental (unintentional), in Toxic effects of substances chiefly nonmedicinal as to source (T51-T65), chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes

T65.851S is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under T65.851 below.
As a secondary diagnosis it is not a CC or MCC, so it doesn't raise the MS-DRG payment.
Exempt from present-on-admission (POA) reporting. (POA Exempt list)

Instructional notes

Also applies, from T65.851: Toxic effect of medetomidine, accidental (unintentional)

These notes sit on T65.851 and apply to every code under it, including T65.851S.

Includes: conditions that are coded here

Toxic effect of medetomidine NOS

Also applies, from T65.85: Toxic effect of medetomidine

These notes sit on T65.85 and apply to every code under it, including T65.851S.

Use additional code: add a second code for this, listed after this one

code to identify associated manifestations, such as:
bradycardia NOS (R00.1)
somnolence, stupor and coma (R40.-)

Also applies, from Toxic effects of substances chiefly nonmedicinal as to source (T51-T65)

These notes sit on T51-T65 and apply to every code under it, including T65.851S.

Excludes1: not coded here, use a different code

contact with and (suspected) exposure to toxic substances (Z77.-)

Use additional code: add a second code for this, listed after this one

code(s):
for all associated manifestations of toxic effect, such as: respiratory conditions due to external agents (J60-J70)
personal history of foreign body fully removed (Z87.821)
to identify any retained foreign body, if applicable (Z18.-)

Other codes under T65.851

Toxic effect of medetomidine, accidental (unintentional)

T65.851AToxic effect of medetomidine, accidental (unintentional), initial encounter
T65.851DToxic effect of medetomidine, accidental (unintentional), subsequent encounter
T65.851SToxic effect of medetomidine, accidental (unintentional), sequela(this code)

MS-DRGs

As the principal diagnosis, this code groups to these MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Poisoning

A poison is any substance that is harmful to your body. You might swallow it, inhale it, inject it, or absorb it through your skin. Any substance can be poisonous if too much is taken. Poisons can include:

Code history

Added in FY2027 (effective October 1, 2026). Before that, these cases were coded as T65.891S (Toxic effect of other specified substances, accidental (unintentional), sequela). No changes since.