Billable / Specific Code
ICD-10-CM Z77.121 is the diagnosis code for Contact with and (suspected) exposure to harmful algae and algae toxins. This code falls under the section "Persons with potential health hazards related to family and personal history and certain conditions influencing health status" within Chapter 21 — Factors influencing health status and contact with health services (Z00-Z99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Understanding where Z77.121 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, Z77.121 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
Z77.121 is the ICD-10-CM diagnosis code for "Contact with and (suspected) exposure to harmful algae and algae toxins". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of Z77.121 is Z77.12 ("Contact with and (suspected) exposure to hazards in the physical environment"). Z77.121 provides a more specific classification within this category.
Z77.121 is located in Section Z77-Z99 — "Persons with potential health hazards related to family and personal history and certain conditions influencing health status" within Chapter 21 of the ICD-10-CM Tabular List.
Use Z77.121 when the patients documented diagnosis matches "Contact with and (suspected) exposure to harmful algae and algae toxins" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Contact with and (suspected) exposure to harmful algae and algae toxins is Z77.121.
Yes, Z77.121 can be used as a primary diagnosis code since it is billable and specific.
Z77.121 is in Chapter 21 of the ICD-10-CM Tabular List.
Yes, Z77.121 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.