ICD-10-CM > S00-T88 > T20-T25 > T22 > T22.4 > T22.43 > T22.439 T22.439 Corrosion of unspecified degree of unspecified upper arm Non-Billable/Non-Specific Codes T22.439A..., initial encounterT22.439D..., subsequent encounterT22.439S..., sequela