ICD-10-CM > S00-T88 > S40-S49 > S40 > S40.8 > S40.82 S40.82 Blister (nonthermal) of upper arm Non-Billable/Non-Specific Codes S40.821Blister (nonthermal) of right upper armS40.821A..., initial encounterS40.821D..., subsequent encounterS40.821S..., sequelaS40.822Blister (nonthermal) of left upper armS40.822A..., initial encounterS40.822D..., subsequent encounterS40.822S..., sequelaS40.829Blister (nonthermal) of unspecified upper armS40.829A..., initial encounterS40.829D..., subsequent encounterS40.829S..., sequela