Sepsis can be viewed by blood routine, blood culture, serum procalcitoninogen, and so on. 1. Blood routine: peripheral blood leukocytes are elevated in sepsis patients, usually with values up to (10-30) × 10^9/L. Neutrophils are markedly elevated, and there may be marked leftward nuclear shift and intracellular toxic granules. However, in some cases of poor immune response and in a few cases of gram-negative bacterial sepsis, the leukocyte count may be normal or decreased, but the neutrophil count is increased. Complicated disseminated intravascular coagulation is associated with thrombocytopenia, and some patients with prolonged disease may also develop anemia. 2. Blood culture: positive result, blood culture is a definite indicator for the diagnosis of sepsis. It is better to collect blood before the application of antimicrobial drugs, when there are chills and high fever, and collect blood in different parts of the body several times and send it to the hospital for examination several times, which can improve the positive rate of culture. If antimicrobial drugs have been applied, magnesium sulfate, β-lactamase or p-aminobenzoic acid should be added to the culture medium to destroy certain antimicrobial drugs, or blood clot culture method should be used. 3. Serum calcitoninogen measurement: it is also of reference significance for the early diagnosis of sepsis.