Bacterial infection, and as a result, sepsis is a formidable complication in patients with new coronavirus infection, and one of the leading factors in hospital mortality. In the context of the COVID-19 pandemic, the economic costs of health care for biochemical monitoring have increased signifcantly. There is a need for a new approach to the analysis and, possibly, structuring of the results of routine studies obtained through a general blood test. The aim of the work is to assess the diagnostic capabilities of the new hematological parameters NEUT-RI – neutrophil reactivity and NEUT-GI – neutrophil granularity obtained using the Sysmex XN hematological analyzer from the standpoint of sepsis diagnostics. We analyzed laboratory data from a sample of patients with coronavirus infection (n = 449). Subsequently, the general statistical population was divided into two groups according to the level of procalcitonin – PCT (cut off = 0.5 ng/ml). With PCT < 0.5 ng/ml, the presence of sepsis was considered as ‘unlikely’, with PCT > 0.5 ng/ml as ‘highly likely’ event. For mathematical data processing, traditional statistical analysis, ROC analysis and the author’s ‘probabilistic approach’ were used. According to the data obtained, at PCT < 0.5 ng/ml, there is a correlation of average strength between C-reactive protein and procalcitonin (r = 0.49, p < 0.05). In the range of high concentrations of procalcitonin (PCT > 0.5 ng/ml), the mathematical relationship between similar biochemical markers is lost. The absence of the informative value of lactate dehydrogenase in terms of the diagnosis of sepsis has been established. According to the research results, NEUT-RI ≥ 56.9 Fl with a probability of 72% (specifcity 62.0%, sensitivity 83.5%) indicates the presence of sepsis. The probability of an alternative prognosis (presence or absence of sepsis) in one or another interval of the NEUT-RI and NEUT-GI values was calculated. The narrow quantitative ranges of the NEUT-RI parameter were identifed, in which the probability of sepsis is absent – 0% (35–45 Fl) and very high – 77% (65–75 Fl).
