ICD-10-CM > S00-T88 > T20-T25 > T21 > T21.3 > T21.35 T21.35 Burn of third degree of buttock Non-Billable/Non-Specific Applicable To Burn of third degree of anus Codes T21.35XA..., initial encounterT21.35XD..., subsequent encounterT21.35XS..., sequela