ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.5 > T23.53 > T23.531 T23.531 Corrosion of first degree of multiple right fingers (nail), not including thumb Non-Billable/Non-Specific Codes T23.531A..., initial encounterT23.531D..., subsequent encounterT23.531S..., sequela