ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.7 > T23.74 > T23.742 T23.742 Corrosion of third degree of multiple left fingers (nail), including thumb Non-Billable/Non-Specific Codes T23.742A..., initial encounterT23.742D..., subsequent encounterT23.742S..., sequela