Sepsis (septicemia) is the invasion of pathogenic bacteria (bacteria and fungi) into the blood circulation, which multiply in the blood and produce toxins, causing a series of infections and toxemia manifestations. The main clinical manifestations are chills, high fever, rash, splenomegaly, and in some patients, migratory lesions. Peripheral blood leukocytes and neutrophils are significantly elevated. Patients may present with infectious shock, diffuse intravascular coagulation (DIC), acute respiratory distress syndrome (ARDS), and multiorgan failure. The disease mainly occurs in immunocompromised patients (such as AIDS, cirrhosis, diabetes, etc.), those who use immunosuppressive drugs and various catheters (especially intravenous catheters), and once the disease is not treated in time, there will be a 30-40% mortality rate. 1, blood routine Peripheral blood leukocytes are significantly elevated, up to (10-30) × 109/L, neutrophils are significantly increased with left shift of the nucleus, and toxic particles can be seen in leukocytes. The total leukocyte count may not be increased or decreased in those with poor body response or in a few cases of Gram-negative bacillus (G-) sepsis, but neutrophils are often increased. In cases of thrombocytopenia or progressive thrombocytopenia, complications of DIC should be noted. 2. Urine routine Urine protein may be present. Red and white blood cells and tubular pattern can be seen in the urine. 3.Blood sedimentation is often increased in hyperthermia. 4.Biochemical examination In combination with ARDS, blood gas analysis may reveal a decrease in oxygen saturation. Liver enzymes ALT, AST, ALP, γ-GT, LDH may be increased in combined with multi-organ failure; bilirubin may be increased in jaundice; serum protein and lipids may be decreased. Creatinine and urea can be elevated in renal failure. BNP is significantly increased in heart failure. CRP and serum calcitonin may be elevated. 5. Pathogenic examination: Gram-positive bacteria (G+) (mainly Staphylococcus aureus, coagulase-negative staphylococci, enterococci, Listeria monocytogenes, etc.); Gram-negative bacteria (G-) (mainly Escherichia coli, Salmonella typhimurium, S. pneumoniae, Pseudomonas, Aspergillus, Enterobacter, Bacillus immobilis, Serratia, etc.); anaerobic bacteria, accounting for 5-10%, with fragile Pseudomonas aeruginosa and Streptococcus pepticus are the most common; fungi with Pseudomonas albicans are the most common, followed by Aspergillus and Trichoderma. The above pathogens can be isolated by blood culture and then identified. Bone marrow, urine, stool, cerebrospinal fluid, chest and abdominal fluid, wound secretions, pus, lower respiratory secretions and other specimens for bacterial culture if necessary, positive results must do drug sensitivity test. 6, G and GM test Aids fungal diagnosis, and fungal infection is considered in combination with clinical when positive. The most important thing in sepsis is to try to clarify the type of pathogenic microorganisms and drug sensitivity results through pathogenetic examination to facilitate clinical treatment. For all kinds of severe DIC, ARDS, MOF, attention should be paid to monitoring, early detection and timely treatment.