Introduction. Clinical and laboratory criteria of the Sepsis-2 Consensus disregard organ dysfunction manifestations and compensatory anti-inflammatory response in septic complications. The aim of the study was to develop a laboratory parameter detecting sepsis at different periods of its course based on a detailed complete blood test considering the degree of pro-inflammatory response to infection, an anti-inflammatory component, presence of a particular sign of the multiple organ failure. Materials and methods. A statistical study included 152 patients with clinical and laboratory manifestations of surgical sepsis who underwent inpatient treatment at the surgical clinical base of the North-Western State Medical University. In the group of patients who had signs of endogenous intoxication, but the diagnosis of sepsis was not confirmed, frequency of verification of septicopyemia at autopsy was identified in every 4th case. Variants of sepsis scoring were determined in accordance with the parameters of the complete blood test.Results. The correlation between the procalcitonin level and the scoring system was noted at 0,5019309, the correlation between the blood lactate level and the scoring system did not exceed 0,542726115. Findings. With a score higher than 7, the diagnosis of severe sepsis is very likely. With a score lower than 4, the presence of severe sepsis, including the development of septicopyemia, is unlikely. Under the condition when a score is equal 5-6 and combined with long periods of the disease, the search for distant foci of septicopyemia and assessment of the prognosis for the secondary sepsis development are priority. Conclusion. The scoring assessment of a simple laboratory investigation (detailed complete blood test), in our opinion, indirectly reflects the presence and period of septic complications. The use of a score system in practical healthcare can improve screening of patients with surgical infection complicated by the development of sepsis at all stages of medical care.