Ultrasensitive C-reactive protein is an acute time-phase protein. Exceeding 5mg/L suggests an increased risk of myocardial infarction and coronary atherosclerosis; exceeding 10mg/L suggests a high likelihood of bacterial infections, which need to be aggressively managed. Ultrasensitive C-reactive protein is an acute time-phase protein synthesized by the liver, with a normal range of 0-3mg/L. It can be elevated in the presence of inflammatory infections, cardiovascular and cerebrovascular problems, and immune system problems. In acute bacterial infections, ultrasensitive C-reactive protein can rise rapidly, exceeding 10 mg/L suggesting the presence of a bacterial infection, and in severe infections it can rise several times or even dozens of times. Ultrasensitive C-reactive protein can decrease after infection control, so the presence of ultrasensitive C-reactive protein greater than 10mg/L needs to be treated with anti-infective therapy. Ultrasensitive C-reactive protein is also one of the predictors of cardiovascular and cerebrovascular disease risk. In acute myocardial infarction, ultrasensitive C-reactive protein can rise sharply and then fall after 3 days. When the ultrasensitive C-reactive protein is greater than 5mg/L, it predicts an increased risk of cardiovascular and cerebrovascular disease, and requires attention and further examination to find the cause.