FIELD : medicine.SUBSTANCE : invention relates to the field of medicine and is a method for assessing the severity of sepsis, including the preparation of blood samples of patients with sepsis for fluorescent in situ hybridization with the subsequent detection of bacteria in blood samples using fluorescent microscopy, characterized in that determine the amount of bacteria adhered on the surface of erythrocytes and placed intraerythrocytically and calculate the integral indicator by the formula : II = 1.527?+?0.333??X1?-?1.116??X2?-?0.137??X3?+?0.033??X4?+?0.061??X5?-?0.184??X6?+?3.242??X7?+?0.71?X8?+?0.888??X9?+?0.336??X10, where : X1 - number of adhered bacteria on the surface of erythrocytes in a patient' s blood sample, treated with the Oligo1 probe; X2 - number of adhered bacteria on the surface of erythrocytes in a patient' s blood sample, treated with the Oligo2 probe; X3 - number of adhered bacteria on the surface of erythrocytes in a patient' s blood sample, treated with the Oligo3 probe; X4 - number of adhered bacteria on the surface of erythrocytes in a patient' s blood sample, treated with the Oligo4 probe; X5 - number of adhered bacteria on the surface of erythrocytes in a patient' s blood sample, treated with the Oligo5 probe; X6 - number of intraerythrocytically placed bacteria in the patient' s blood sample treated with the Oligo1 probe; X7 - number of intraerythrocytically placed bacteria in the patient' s blood sample treated with the Oligo2 probe; X8 - number of intraerythrocytically placed bacteria in the patient' s blood sample treated with the Oligo3 probe; X9 - number of intraerythrocytically placed bacteria in the patient' s blood sample treated with the Oligo4 probe; X10 - number of intraerythrocytically placed bacteria in the patient' s blood sample treated with the Oligo5 probe, however, when a value of the integral indicator is less than 2.5, the severity of sepsis is considered light, with a value from 2.5 to 5.6 - moderate, and with a value greater than 5.6 - heavy.EFFECT : method allows to increase the accuracy of early diagnosis of sepsis and assess the severity of the disease.1 cl, 2 dwg, 4 tbl, 4 ex