ICD-10-CM > S00-T88 > T51-T65 > T58 > T58.8 > T58.8X > T58.8X4 T58.8X4 Toxic effect of carbon monoxide from other source, undetermined Non-Billable/Non-Specific Codes T58.8X4A..., initial encounterT58.8X4D..., subsequent encounterT58.8X4S..., sequela