A high level of neutrophils can indicate an infection, gout or leukemia, as stated by the National Institutes of Health. The increase can also be caused by an allergic reaction.
An increased level of neutrophils means that a person's white blood cell count has increased, according to WebMD. This is typically discovered during a complete blood count test. When the high level of neutrophils or some other abnormal blood levels are discovered, more tests may be performed to find out the cause of the increase. Only a doctor can diagnose a condition or determine the cause of the elevated level of neutrophils.