Basophils are the least common leukocyte, range from 0.4%-1.0%. High basophils may be caused several conditions, including:

• Viral infections, such as varicella
• Myeloproliferative diseases, such as chronic myelogenous leukemia, polycythemia vera and myelofibrosis
• Inflammatory processes, such as inflammatory bowel disease, chronic dermatitis, asthma and chronic sinusitis
• Hodgkin’s lymphoma
• Hemolytic anemia
• Following splenectomy
• Endocrine causes, such as hypothyroidism and increased estrogen.