Eosinophilia

This code represents an abnormally high number of eosinophils, a type of white blood cell, in the peripheral blood. Eosinophilia is a laboratory finding rather than a disease itself, often indicating an underlying allergic reaction, parasitic infection, or certain inflammatory conditions.

Assign this code when medical record documentation explicitly states eosinophilia as a diagnostic finding. This is typically supported by laboratory results showing an elevated eosinophil count, often noted in a complete blood count (CBC) with differential. Use this code when the specific cause of the eosinophilia is unknown or not yet definitively diagnosed.

• Always code the underlying cause of the eosinophilia if it is known and documented (e.g., allergic rhinitis, parasitic infection).
• This code should be used as a secondary diagnosis when the primary reason for the encounter is the investigation or treatment of the underlying condition.
• Do not confuse with eosinophilic disorders of specific organs (e.g., eosinophilic esophagitis), which have more specific codes.