noun. an abnormal increase in the number of white blood cells in the blood as a result of infection (as in leukemia).
1. Noun, singular or mass A baby born to a mother with chorioamnionitis may have leukocytosis if she is born with an infection and her body is trying to fight off invading bacteria. 2. Verb, past participle Even a mild infection can be serious if you have leukocytosis**, because your body can’t fight off the infection.