ICD-10-CM > S00-T88 > T51-T65 > T65 > T65.8 > T65.82 > T65.824 T65.824 Toxic effect of harmful algae and algae toxins, undetermined Non-Billable/Non-Specific Codes T65.824A..., initial encounterT65.824D..., subsequent encounterT65.824S..., sequela