Dear Dr. Roach: My eosinophil count on routine blood test came back at 6.7 (normal 3-5). Should I be concerned? I do have asthma. — E.P.

Answer: Eosinophils are a normal component of blood. They are a specialized white blood cell that is found normally in small amounts. The number you are giving is a percentage of the total, and in people with white blood cell counts on the low end of normal, it may represent a normal eosinophil count (0-500 per microliter of blood).

People with asthma often have slightly elevated eosinophil levels. Odds are, this level is not something to worry about, but talk to your doctor at your next appointment to get more information.