ICD-10-CM > S00-T88 > T51-T65 > T57 > T57.3 > T57.3X > T57.3X4 T57.3X4 Toxic effect of hydrogen cyanide, undetermined Non-Billable/Non-Specific Codes T57.3X4A..., initial encounterT57.3X4D..., subsequent encounterT57.3X4S..., sequela