ICD-10-CM > S00-T88 > T33-T34 > T34 > T34.8 > T34.82 > T34.821 T34.821 Frostbite with tissue necrosis of right foot Non-Billable/Non-Specific Codes T34.821A..., initial encounterT34.821D..., subsequent encounterT34.821S..., sequela