ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.7 > T23.71 > T23.719 T23.719 Corrosion of third degree of unspecified thumb (nail) Non-Billable/Non-Specific Codes T23.719A..., initial encounterT23.719D..., subsequent encounterT23.719S..., sequela