We defined Systemic inflammation (SI) as a "typical, multi-syndrome, phase-specific pathological process, developing from systemic damage and characterized by the total inflammatory reactivity of endotheliocytes, plasma and blood cell factors, connective tissue and, at the final stage, by microcirculatory disorders in vital organs and tissues." The goal of the work: to determine methodological approaches and particular methodical solutions for the problem of identification of SI as a common pathological process. SI can be defined by the presence in plasma of systemic proinflammatory cell stress products-cytokines and other inflammatory mediators, and also by the complexity of other processes signs. We have developed 2 scales: 1) The Reactivity Level scale (RL)-from 0 to 5 points: 0-normal level; RL-5 confirms systemic nature of inflammatory mediator release, and RL- 2-4 defines different degrees of event probability. 2) The SI scale, considering additional criteria along with RL, addresses more integral criteria of SI: the presence of ≥ 5 points according to the SI scale proves the high probability of SI developing. To calculate the RL scale, concentrations of 4 cytokines (IL-6, IL-8, IL-10, TNF-α) and C-reactive protein in plasma were examined. Additional criteria of the SI scale were the following: D-dimers>500ng/ml, cortisol>1380 or <100nmol/l, troponin I≥0.2ng/ml and/or myoglobin≥800ng/ml. 422 patients were included in the study with different septic (n-207) and aseptic (n-215) pathologies. In 190 cases (of 422) there were signs of SI (lethality 38.4%, n-73). In only 5 of 78 cases, lethality was not confirmed by the presence of SI. SI was registered in 100% of cases with septic shock (n-31). There were not significant differences between AU-ROC of CR, SI scale and SOFA to predict death in patients with sepsis and trauma.