ICD-10-CM > S00-T88 > T33-T34 > T33 > T33.8 > T33.81 > T33.819 T33.819 Superficial frostbite of unspecified ankle Non-Billable/Non-Specific Codes T33.819A..., initial encounterT33.819D..., subsequent encounterT33.819S..., sequela