ICD-10 Code A77.40 – Ehrlichiosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A77.40 – Ehrlichiosis, unspecified
What it is
A77.40 identifies ehrlichiosis when the record does not name a specific Ehrlichia species or type. Use it for a documented ehrlichial infection without further detail.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include an acute febrile illness with headache, malaise, myalgia, and sometimes rash or abnormal laboratory results.
When to use this code
Use this code when the clinician documents ehrlichiosis but does not specify the organism or subtype. It also fits cases where the chart confirms ehrlichial infection and no more precise diagnosis is available. Check documentation if the note names a different tick-borne illness.
Do not use for
Do not use A77.40 if the record specifies a different Ehrlichia species or another tick-borne disease. If the diagnosis is only suspected, or documentation is unclear, check documentation.
Coding tip
Code the most specific ehrlichiosis term documented, and query for organism detail when the note only says “ehrlichiosis.”