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ICD-10-CM 2027

ICD-10 code for red tide

T65.82

Toxic effect of harmful algae and algae toxins

Header — needs a more specific code

From the official ICD-10-CM alphabetic index entry “Red tide”. Page updated September 29, 2026.

About coding red tide

The ICD-10-CM code for red tide is T65.82 (Toxic effect of harmful algae and algae toxins).

Within T65.8 (toxic effect of other specified substances), T65.82 is specifically for toxic effect of harmful algae and algae toxins. Related codes cover latex (T65.81), fiberglass (T65.83), xylazine (T65.84), medetomidine (T65.85) and other specified substances (T65.89).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Common questions about red tide ICD-10 codes

What is the ICD-10 code for red tide?

T65.82 — Toxic effect of harmful algae and algae toxins (a header code; report a more specific subcode).

Is T65.82 billable?

No. T65.82 is a header code. Report one of its more specific subcodes instead.