T65.821ABillable
Toxic effect of harmful algae and algae toxins, accidental (unintentional), initial encounter
Short description: Toxic effect of harmful algae and algae toxins, acc, init
- Chapter
- 19. Injury, poisoning and certain other consequences of external causes
- Category
- T65
- Effective date
- October 1, 2026
Related codes in category T65
T65Toxic effect of other and unspecified substancesT65.0Toxic effect of cyanidesT65.0XToxic effect of cyanidesT65.0X1Toxic effect of cyanides, accidental (unintentional)T65.0X1AToxic effect of cyanides, accidental (unintentional), initYesT65.0X1DToxic effect of cyanides, accidental (unintentional), subsYesT65.0X1SToxic effect of cyanides, accidental, sequelaYesT65.0X2Toxic effect of cyanides, intentional self-harmT65.0X2AToxic effect of cyanides, intentional self-harm, init encntrYesT65.0X2DToxic effect of cyanides, intentional self-harm, subs encntrYesT65.0X2SToxic effect of cyanides, intentional self-harm, sequelaYesT65.0X3Toxic effect of cyanides, assault
Frequently asked questions
What is ICD-10 code T65.821A?
T65.821A is an ICD-10-CM diagnosis code for Toxic effect of harmful algae and algae toxins, accidental (unintentional), initial encounter.
Is T65.821A a billable code?
Yes. T65.821A is billable and specific enough to be used on a claim.
What ICD-10-CM chapter is T65.821A in?
T65.821A falls under Chapter 19: Injury, poisoning and certain other consequences of external causes.
When did T65.821A become effective?
T65.821A has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to T65.821A?
T65.821A belongs to category T65, which includes 12 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.