White blood cells of 12×10^9/L may be accompanied by fever, if this is the case, it is recommended to consult a professional doctor for standardized and reasonable diagnosis and treatment. The normal range of white blood cells is 4×10^9~10×10^9/L, if it exceeds the highest normal value of 10×10^9/L, it means that there may be inflammation in the patient’s body at this time, and the inflammation in the body will produce a large number of inflammatory factors, which will act on the central system, resulting in an imbalance between the two, which may lead to the body to produce a fever. If the white blood cell count is found to be increased after seeking medical treatment, it is recommended to seek professional doctors to carry out reasonable and standardized diagnosis and treatment in a timely manner.