ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.6 > T23.62 > T23.621 T23.621 Corrosion of second degree of single right finger (nail) except thumb Non-Billable/Non-Specific Codes T23.621A..., initial encounterT23.621D..., subsequent encounterT23.621S..., sequela