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T65.821

Non-billable

Toxic effect of harmful algae and algae toxins, accidental (unintentional)

T65.821 is the ICD-10-CM code for Toxic effect of harmful algae and algae toxins, accidental (unintentional). It is a non-billable category code — use a more specific child code such as T65.821A for billing.

Status
Header (non-billable)
Chapter
S00-T88
Parent
T65.82
Subcodes
3
Edition
FY2026

S00-T88 Injury, poisoning and certain other consequences of external causes

Includes

  • •Toxic effect of harmful algae and algae toxins NOS

Frequently asked questions

What is ICD-10 code T65.821?
T65.821 is the ICD-10-CM code for "Toxic effect of harmful algae and algae toxins, accidental (unintentional)". It falls under S00-T88 Injury, poisoning and certain other consequences of external causes.
Is T65.821 a billable code?
No — T65.821 is a non-billable header code. Use a more specific child code (such as T65.821A) for billing.
What are the subcodes of T65.821?
T65.821 has 3 more specific child codes, including T65.821A, T65.821D, T65.821S.

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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