ICD-10-CM > S00-T88 > T20-T25 > T22 > T22.4 > T22.41 > T22.412 T22.412 Corrosion of unspecified degree of left forearm Non-Billable/Non-Specific Codes T22.412A..., initial encounterT22.412D..., subsequent encounterT22.412S..., sequela