ICD-10-CM > S00-T88 > T33-T34 > T34 > T34.8 > T34.81 > T34.812 T34.812 Frostbite with tissue necrosis of left ankle Non-Billable/Non-Specific Codes T34.812A..., initial encounterT34.812D..., subsequent encounterT34.812S..., sequela