ICD-10-CM > S00-T88 > T20-T25 > T25 > T25.4 > T25.42 > T25.421 T25.421 Corrosion of unspecified degree of right foot Non-Billable/Non-Specific Codes T25.421A..., initial encounterT25.421D..., subsequent encounterT25.421S..., sequela