T58 – Toxic effect of carbon monoxide

ICD-10-CM 2027 diagnosis code · Toxic effects of substances chiefly nonmedicinal as to source

Non-billable header

ICD-10-CM code T58

Code: T58 (claims format: T58)
Description: Toxic effect of carbon monoxide
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 19. Injury, poisoning and certain other consequences of external causes (S00-T88)
Block: T51-T65 Toxic effects of substances chiefly nonmedicinal as to source

Billable codes under T58

T58 is a header code and cannot be used on claims. Choose the most specific code:

T58.0 – Toxic effect of carbon monoxide from motor vehicle exhaustHeader (more codes below)
T58.1 – Toxic effect of carbon monoxide from utility gasHeader (more codes below)
T58.2 – Toxic effect of carbon monoxide from incomplete combustion of other domestic fuelsHeader (more codes below)
T58.8 – Toxic effect of carbon monoxide from other sourceHeader (more codes below)
T58.9 – Toxic effect of carbon monoxide from unspecified sourceHeader (more codes below)

7th character values

Codes in this category need a 7th character to describe the encounter or episode of care (use placeholder X for empty positions).

Character	Meaning
`A`	initial encounter
`D`	subsequent encounter
`S`	sequela

Notes for T58

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

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

Block T51-T65

Excludes1 (not coded here):

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

Use additional code:

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.-)

Notes:

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.

Frequently asked questions

What is ICD-10 code T58?

T58 is the ICD-10-CM code for toxic effect of carbon monoxide, in the block T51-T65 (Toxic effects of substances chiefly nonmedicinal as to source).

Is T58 a billable code?

No. T58 is a header code with more specific child codes; report one of the billable codes listed above.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.