ICD-10 Code A20.9 – Plague, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A20.9 – Plague, unspecified
What it is
A20.9 identifies plague when the specific clinical form is not documented. Use it for a confirmed plague diagnosis without further detail, such as bubonic, septicemic, or pneumonic type.
Clinical signs
Clinical features vary; refer to documentation. Plague may present with acute febrile illness, lymph node swelling, sepsis, or pneumonia, depending on the form. Confirmed exposure or diagnostic evidence should support the diagnosis.
When to use this code
Use A20.9 when the provider documents plague but does not specify the type. It also fits cases where the chart confirms plague infection and no further classification is available. If the record later names a specific form, code that more precise diagnosis instead.
Do not use for
Do not use A20.9 for suspected plague without confirmation, or when another diagnosis better explains the illness. If the record identifies a specific plague type, do not default to unspecified coding.
Coding tip
Check the final provider statement for the exact plague type before assigning A20.9.