Toxic effect of harmful algae and algae toxins, undet, subs

This code signifies a patient presenting with adverse health effects due to exposure to harmful algae or their toxins, where the specific intent or circumstances of the exposure are not documented. This diagnosis is used when the patient is receiving follow-up care for the toxic effects after the initial treatment.

Apply this code for patients returning for ongoing management of symptoms like gastrointestinal distress, neurological issues, or skin irritation previously attributed to algal toxin exposure. This is appropriate for subsequent visits after the initial diagnosis and treatment, when the provider is still investigating the source or intent of the exposure.

• Ensure documentation clearly indicates a follow-up encounter for the toxic effect.
• Do not use this code for initial encounters; instead, use the appropriate initial encounter code (T65.824A).
• Consider additional codes for specific symptoms or complications arising from the toxic effect.