2027 ICD-10-CM Diagnosis Code T65.842AToxic effect of xylazine, intentional self-harm, initial encounter

ICD-10-CM Codes›S00–T88›T51-T65›T65

ICD-10-CM T65.842A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T65.842A is a billable ICD-10-CM diagnosis code for toxic effect of xylazine, intentional self-harm, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 917 through 918. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under External cause codes: intent of injury, self-harm; External cause codes: poisoning by drug; and Suicidal ideation/attempt/intentional self-harm.

For Medicare Advantage risk adjustment, T65.842A maps to CMS-HCC Category 155 (Major Depression, Moderate or Severe, without Psychosis) under the V28 model, adding a risk factor of about 0.299 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
T65.842A
Billable Status
Yes — Valid for Submission
Code Describes
Toxic effect of xylazine, intentional self-harm, initial encounter
Short Description
Toxic effect of xylazine, self-harm, initial encounter
Parent Code
T65.842
Toxic effect of xylazine, intentional self-harm

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT51-T65Toxic effects of substances chiefly nonmedicinal as to source
CategoryT65Toxic effect of other and unspecified substances
This CodeT65.842AToxic effect of xylazine, intentional self-harm, initial encounter

Medicare Risk Adjustment (HCC)Billing

T65.842A maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 155— Major Depression, Moderate or Severe, without Psychosis
Payment HCC · PY 2027 one of 371 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.299
community, non-dual, aged · ranges 0.108–0.316 across segments
Hierarchy
Superseded by HCC 151, HCC 152, HCC 153, and HCC 154
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Other CMS Models
PACE (CMS-HCC V22): HCC 58 · ESRD (V21): HCC 58 · ESRD (V24): HCC 59
ESRD V21 weights: 0.091 dialysis, 0.217–0.260 functioning graft · ESRD V24 weights: 0.066 dialysis, 0.129–0.259 functioning graft
Part D (RxHCC)
RxHCC 132 — Depression
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Toxic effect of other and unspecified substances (T65). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T65.842A: its own notes plus those printed at T65.84, T65, block T51-T65, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • contact with and (suspected) exposure to toxic substances (Z77.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From T65.84 Toxic effect of xylazine applies to 12 codes
  • code(s) for all associated manifestations, such as:
  • cellulitis and acute lymphangitis (L03.-)
  • cutaneous abscess, furuncle and carbuncle (L02.-)
  • non-pressure chronic ulcer of lower limb, not elsewhere classified (L97.-)
  • non-pressure chronic ulcer of skin, not elsewhere classified (L98.4-)
From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • 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.-)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Notes

General instructions on how these codes are used.

From Block T51-T65 Toxic effects of substances chiefly nonmedicinal as to source applies to 1,680 codes
  • When no intent is indicated code to accidental. Undetermined intent is only for use when there is specific documentation in the record that the intent of the toxic effect cannot be determined.
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
  • The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From T65 Toxic effect of other and unspecified substances applies to 192 codes
  • The appropriate 7th character is to be added to each code from category T65
Values for category T65 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR EXT021
External cause codes: intent of injury, self-harm
Default principal diagnosis: inpatient No · outpatient No
CCSR EXT014
External cause codes: poisoning by drug
Default principal diagnosis: inpatient No · outpatient No
CCSR MBD012
Suicidal ideation/attempt/intentional self-harm
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR INJ023
Toxic effects, initial encounter
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Xylazine

    an adrenergic alpha-2 agonist used as a sedative, analgesic and centrally acting muscle relaxant in veterinary medicine.

Table of Drugs and ChemicalsClinical

Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.

SubstanceAccidentalSelf-harmAssaultUndeter­minedAdverse
Effect		Under­dosing
XylazineT65.841T65.842T65.843T65.844––

Patient EducationClinical

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:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code History & ChangesHistory

Replacement T65.842A replaces the following previously assigned code(s):

  • T65.892A - Toxic effect of oth substances, intentional self-harm, init
FY 2026AddedAdded to the ICD-10-CM code setEffective October 1, 2025.
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About T65.842AOverview

What is the ICD-10 code for toxic effect of xylazine, intentional self-harm, initial encounter?

The ICD-10-CM code for toxic effect of xylazine, intentional self-harm, initial encounter is T65.842A (sometimes written as T65842A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is T65.842A (Toxic effect of xylazine, intentional self-harm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report toxic effect of xylazine, intentional self-harm, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in T65.842A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for toxic effect of xylazine, intentional self-harm, such as an emergency visit or first evaluation.

What MS-DRG does T65.842A group to?

When toxic effect of xylazine, intentional self-harm, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 918, 917, with relative weights from 0.8716 to 1.5698 depending on complications. Higher weights mean higher Medicare reimbursement.

Can T65.842A be reported with a code from Z77?

Not as a rule. The Excludes1 note at block T51-T65, which applies to T65.842A, lists "contact with and (suspected) exposure to toxic substances (Z77.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What HCC is T65.842A?

T65.842A (toxic effect of xylazine, intentional self-harm, initial encounter) maps to CMS-HCC Category 155 (Major Depression, Moderate or Severe, without Psychosis), commonly written as HCC 155, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 132.

Does T65.842A risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, T65.842A adds a risk adjustment factor of about 0.299 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.108 to 0.316 depending on the payment segment). A more severe related category (HCC 151, HCC 152, HCC 153, and HCC 154) supersedes it when both are reported. See the full factor table on the HCC 155 category page.