T59.7X
Toxic effect of carbon dioxide
T59.7X is a non-billable ICD-10-CM code header for toxic effect of carbon dioxide. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are T59.7X1 Toxic effect of carbon dioxide, accidental (unintentional); T59.7X2 Toxic effect of carbon dioxide, intentional self-harm; T59.7X3 Toxic effect of carbon dioxide, assault and T59.7X4 Toxic effect of carbon dioxide, undetermined. Its coding notes include a Use additional code instruction, 2 Excludes1 entries and 2 Excludes2 entries.
7th characters
Every code below needs one of these (defined at T59).
The appropriate 7th character is to be added to each code from category T59
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
T36-T65 codes already include the substance and the intent, so no additional external cause code is required. Do not code directly from the Table of Drugs and Chemicals.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (5 notes)
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (2 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Includes
Further defines or gives examples of the content of the category.
- aerosol propellants
Notes
Also from chapter/block level (3 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.
- 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.