Ultrasensitive C-reactive protein is abbreviated as CRP, the normal value is 0-5mg/L. C-reactive protein is an acute reaction to the complex formed by the C polysaccharide reaction of Streptococcus pneumoniae, and is prone to abnormal elevation when some diseases occur. For example, various infections, bronchitis, lung infections, nephritis, infective endocarditis, urinary tract infections, connective tissue diseases, neoplastic diseases, and rheumatic immune system diseases can cause an increase in this indicator, so this indicator is not significantly specific. In case of elevation of the above-mentioned indexes, it is necessary to conduct relevant medical examination and further treatment according to the patient’s symptoms, signs and auxiliary examinations. The day before the reaction protein test, no fatty food or water should be consumed after 12:00 p.m. in order to ensure the accuracy of the ultrasensitive C-reactive protein the next morning.