Fever in children is commonly caused by the invasion of pathogens that cause an inflammatory response that leads to fluctuations in body temperature. Common pathogens include viruses, bacteria, rickettsia, chlamydia, mycoplasma, etc. Blood tests are performed when a child has a fever to check for viral, bacterial or other pathogenic infections. This is a good way to identify the cause of the disease, so that you can choose a clear diagnosis and treatment plan based on the test results. At this time, you can feed more warm water and warm juice to take away the body heat and promote the body temperature to drop. At the same time, you can choose anti-viral, or anti-bacterial, or other pathogenic treatment according to the blood test.