Is ICD-10-CM code T58 billable?

No, T58 (Toxic effect of carbon monoxide) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code T58 belong to?

T58 belongs to Chapter 19 of the ICD-10-CM tabular list: S00–T88 (Injury, Poisoning and Certain Other Consequences of External Causes).

T58Not billable, use a more specific code below

Toxic effect of carbon monoxide

In Toxic effects of substances chiefly nonmedicinal as to source (T51-T65), chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes

60 billable codes under T58: none are a CC or MCC; 5 map to HCC 155 (Major Depression, Moderate or Severe, without Psychosis).An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

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

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 T58.

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.-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Section I.C.19.e Adverse Effects, Poisoning, Underdosing and Toxic Effects (page 82), covers T58
For adverse effects, code the effect first, then T36-T50 with character 5. Sequence poisonings (unknown intent coded accidental) and toxic effects (T51-T65) first; underdosing (character 6) is never first-listed.

All codes under T58

T58 can't be used on a claim. Pick a billable code below; grey headings group them.

T58 MS-DRGs

As the principal diagnosis, the billable codes under T58 group to MS-DRG 917, 918, 922, 923, 949, or 950 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 917 Poisoning and Toxic Effects of Drugs with MCC (20 of 60 codes)
DRG 918 Poisoning and Toxic Effects of Drugs without MCC (20 of 60 codes)
DRG 922 Other Injury, Poisoning and Toxic Effect Diagnoses with MCC (20 of 60 codes)
DRG 923 Other Injury, Poisoning and Toxic Effect Diagnoses without MCC (20 of 60 codes)
DRG 949 Aftercare with CC/MCC (20 of 60 codes)
DRG 950 Aftercare without CC/MCC (20 of 60 codes)

Other codes that refer to T58

Notes on these codes point to T58.

R09.0 Excludes1: asphyxia due to carbon monoxide (T58.-)
T71 Excludes1: asphyxia from carbon monoxide (T58.-)

About the condition

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

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. You can be poisoned by breathing them in. The most common symptoms of CO poisoning are:

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.