ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.3 > T23.31 > T23.312 T23.312 Burn of third degree of left thumb (nail) Non-Billable/Non-Specific Codes T23.312A..., initial encounterT23.312D..., subsequent encounterT23.312S..., sequela