2026 ICD-10-CM Diagnosis Code T58Toxic effect of carbon monoxide

ICD-10-CM Codes›S00–T88›T51-T65›T58

ICD-10-CM T58
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T58 is a non-billable ICD-10-CM category code for toxic effect of carbon monoxide, so it cannot be submitted on claims. Use a more specific code from this category instead, such as T58.01XA, T58.01XD, T58.01XS, and T58.02XA.

Code Identity

ICD-10-CM Code
T58
Billable Status
No — Non-Billable Category
Code Describes
Toxic effect of carbon monoxide
Chapter
T51-T65
Toxic effects of substances chiefly nonmedicinal as to source

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT51-T65Toxic effects of substances chiefly nonmedicinal as to source
CategoryT58Toxic effect of carbon monoxide
This CodeT58Toxic effect of carbon monoxide

Specific Coding for Toxic effect of carbon monoxideOverview

Non-specific codes like T58 require more characters. Use one of these billable codes instead:

  • T58.0 for Toxic effect of carbon monoxide from motor vehicle exhaust

  • T58.01 for Toxic effect of carbon monoxide from motor vehicle exhaust, accidental (unintentional)

  • T58.02 for Toxic effect of carbon monoxide from motor vehicle exhaust, intentional self-harm

  • T58.03 for Toxic effect of carbon monoxide from motor vehicle exhaust, assault

  • T58.04 for Toxic effect of carbon monoxide from motor vehicle exhaust, undetermined

  • T58.1 for Toxic effect of carbon monoxide from utility gas

  • T58.11 for Toxic effect of carbon monoxide from utility gas, accidental (unintentional)

  • T58.12 for Toxic effect of carbon monoxide from utility gas, intentional self-harm

  • T58.13 for Toxic effect of carbon monoxide from utility gas, assault

  • T58.14 for Toxic effect of carbon monoxide from utility gas, undetermined

  • T58.2 for Toxic effect of carbon monoxide from incomplete combustion of other domestic fuels

  • T58.2X for Toxic effect of carbon monoxide from incomplete combustion of other domestic fuels

  • T58.8 for Toxic effect of carbon monoxide from other source

  • T58.8X for Toxic effect of carbon monoxide from other source

  • T58.9 for Toxic effect of carbon monoxide from unspecified source

  • T58.91 for Toxic effect of carbon monoxide from unspecified source, accidental (unintentional)

  • T58.92 for Toxic effect of carbon monoxide from unspecified source, intentional self-harm

  • T58.93 for Toxic effect of carbon monoxide from unspecified source, assault

  • T58.94 for Toxic effect of carbon monoxide from unspecified source, undetermined

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Toxic effect of carbon monoxide (T58). 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 2026, published by CMS and the National Center for Health Statistics.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Includes

  • asphyxiation from carbon monoxide
  • toxic effect of carbon monoxide from all sources

7th Character Note

  • The appropriate 7th character is to be added to each code from category T58

7th Character

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

Patient EducationClinical

Carbon Monoxide Poisoning

Carbon monoxide (CO) is a gas that has no odor or color. But it is very dangerous. It can cause sudden illness and death. CO is found in combustion fumes, such as those made by cars and trucks, lanterns, stoves, gas ranges and heating systems. CO from these fumes can build up in places that don't have a good flow of fresh air.

Read the full article at MedlinePlus

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

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T58Overview

Is T58 (Toxic effect of carbon monoxide) a billable code?

No. This is a category header that groups the codes for toxic effect of carbon monoxide, and headers cannot be submitted on claims. Claims for toxic effect of carbon monoxide need a more specific code from this category, such as T58.01XA, T58.01XD, and T58.01XS.