R09.0 vs T58
R09.0 (Asphyxia and hypoxemia) compared with T58 (Toxic effect of carbon monoxide), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. R09.0 carries an Excludes1 note covering T58: “asphyxia due to carbon monoxide (T58.-)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| R09.0Asphyxia and hypoxemia | T58Toxic effect of carbon monoxide | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header Report instead: T58.01XA, T58.01XD, T58.01XS, T58.02XA, T58.02XD |
| Classification | R00-R99 — Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Asphyxia and hypoxemia is a non-billable ICD-10-CM category code (R09.0). | Toxic effect of carbon monoxide is a non-billable ICD-10-CM category code (T58). |
| 7th character | — | The appropriate 7th character is to be added to each code from category T58 |
| Includes | — | asphyxiation from carbon monoxide toxic effect of carbon monoxide from all sources |
| 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) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources