ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.4 > T23.44 > T23.442 T23.442 Corrosion of unspecified degree of multiple left fingers (nail), including thumb Non-Billable/Non-Specific Codes T23.442A..., initial encounterT23.442D..., subsequent encounterT23.442S..., sequela