Eat crayfish after the fever phenomenon, need to improve the examination, including routine blood tests, C-reactive protein test, as well as other accompanying symptoms according to the choice of test items and so on. 1 routine blood tests: mainly through the number of white blood cells, neutrophils and lymphocytes to determine the number of infections, as well as viral infections or bacterial infections caused by fever. 2. C-Reactive Protein Test: Elevated levels of C-Reactive Protein are indicative of inflammation caused by infection in the body and are an important basis for diagnosing infection. 3. Choose different tests according to the accompanying symptoms: for example, if the fever is accompanied by diarrhea, the routine stool test can be improved; if the fever is accompanied by rash and itching, the allergen test needs to be improved; if there is a cough, the chest X-ray and other tests need to be improved. Doctors will also prescribe other necessary tests such as kidney function, liver function, electrocardiogram and other tests according to the specific accompanying symptoms. Due to the many causes of fever, the specific situation needs to be analyzed after the doctor’s consultation and in conjunction with the clinical manifestations.