ICD-10 Code A21 – Tularemia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A21 – Tularemia
What it is
A21 identifies tularemia, a zoonotic infection caused by Francisella tularensis. Use it when the record documents tularemia without a more specific site or type.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include fever, chills, localized skin ulceration, lymph node swelling, conjunctivitis, or respiratory symptoms depending on exposure route.
When to use this code
Use A21 when the provider diagnoses tularemia and the chart does not support a more specific ICD-10-CM subcategory. It may apply after tick, deer fly, animal, or contaminated-water exposure when tularemia is confirmed or treated as the working diagnosis. Code the documented form if the record specifies a particular presentation.
Do not use for
Do not use A21 for nonspecific fever, lymphadenitis, or skin ulcers without documented tularemia. If the record only says suspected exposure, check documentation.
Coding tip
Review the note for the documented clinical form and exposure history before assigning the unspecified code.