ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.4 > T23.42 > T23.429 T23.429 Corrosion of unspecified degree of unspecified single finger (nail) except thumb Non-Billable/Non-Specific Codes T23.429A..., initial encounterT23.429D..., subsequent encounterT23.429S..., sequela