T58.91XS — Toxic effect of carbon monoxide from unspecified source, accidental (unintentional), sequela
Is T58.91XS billable?
Yes, but T58.91XS is an unspecified code. T58.91XS is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, T58.91XS is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting T58.91XS — the more specific alternatives are listed below.
More specific alternatives
- T58.01XSToxic effect of carbon monoxide from motor vehicle exhaust, accidental (unintentional), sequela
- T58.11XSToxic effect of carbon monoxide from utility gas, accidental (unintentional), sequela
- T58.2X1SToxic effect of carbon monoxide from incomplete combustion of other domestic fuels, accidental (unintentional), sequela
- T58.8X1SToxic effect of carbon monoxide from other source, accidental (unintentional), sequela
T58.91XS at a glance
| Code | T58.91XS |
|---|---|
| Description | Toxic effect of carbon monoxide from unspecified source, accidental (unintentional), sequela |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "S" | sequela |
What does the 7th character "S" mean in T58.91XS?
In T58.91XS, the 7th character S means sequela. The 7th character is required for T58.91XS to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does T58.91XS group to?
T58.91XS sits in MDC 21 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 922Other Injury, Poisoning and Toxic Effect Diagnoses with MCCmedical
- 923Other Injury, Poisoning and Toxic Effect Diagnoses without MCCmedical
Excludes1 — never code together — inherited from T51-T65
The conditions below can never be reported together with T58.91XS on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- contact with and (suspected) exposure to toxic substances (Z77.-)
Use additional code — inherited from Chapter 19
Report an additional code alongside T58.91XS to fully describe the condition. T58.91XS is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Use additional code — inherited from T51-T65
Report an additional code alongside T58.91XS to fully describe the condition. T58.91XS is sequenced first.
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T58.91XS, but a patient may have both at the same time. When documentation supports it, T58.91XS and the excluded code may both be reported.
How long has T58.91XS existed?
T58.91XS has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.