Eosinophils are white blood cells that fight disease. A doctor can check your eosinophil level with a blood or tissue test. Eosinophilia is the condition that results when a person has a higher-than-normal amount of eosinophils. Eosinophilia usually indicates a parasitic infection, an allergic reaction, or cancer. Before you get too worried about your white blood cells fighting off illnesses, keep reading to learn more about eosinophils and the related condition. We’ll look at symptoms, causes, diagnosis, and when to see a doctor.

1. Blood Testing for Eosinophils

A regular blood test is called a complete blood count and will be able to tell you whether you have high or low (or normal) levels of eosinophils. If your absolute eosinophil count is more than 500 per microliter of blood, you may have eosinophilia. Also, if your eosinophil count is more than 1500 per every microliter of blood, you could have a condition called hypereosinophilia.