Fever with elevated C-reactive protein is indicative of inflammation in the body and can be attributed to a variety of diseases, which need to be combined with multiple examinations such as blood count, immune index, chest CT, blood sedimentation and PPD to clarify the cause. Commonly there are: 1. Infection. If the leukocytes, neutrophils and C-reactive protein are elevated with fever, the infection may be considered, which should be combined with the symptoms and auxiliary examinations to identify the foci of infection and provide symptomatic anti-infection treatment. 2. If C-reactive protein is elevated with fever, night sweats, malaise, wasting, increased sedimentation, and positive 72hPPD, further investigation of tuberculosis is required. 3. Connective tissue disease. Fever, high C-reactive protein, fast sedimentation, ineffective antibiotic treatment, accompanied by joint pain, erythema of skin nodules, and abnormal immune indexes, connective tissue disease is considered. In addition, tumors, infections with specific pathogens, and vaccinations can cause fever with elevated C-reactive protein.