ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.5 > T23.51 > T23.512 T23.512 Corrosion of first degree of left thumb (nail) Non-Billable/Non-Specific Codes T23.512A..., initial encounterT23.512D..., subsequent encounterT23.512S..., sequela