METHOD FOR DIAGNOSING THE ACTIVITY OF INFLAMMATORY BOWEL DISEASES BASED ON A COMBINATION OF ELECTRICAL AND VISCOELASTIC PARAMETERS OF ERYTHROCYTES Russian patent published in 2022 - IPC G01N33/68 G01N27/447 G01N27/48 G16C60/00 G01N1/28 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely gastroenterology, and can be used to diagnose the degree of activity of inflammatory bowel diseases. The level of fecal calprotectin is determined as follows. Patients’ erythrocytes are sampled, samples are placed in a 3.65-3.85% citrate buffer in a ratio of 9:1, after 5-20 minutes, a sample of 9-11 µl is injected into a 0.3 M sucrose solution of 285-295 µl and mixed. The resulting cell suspension with a volume of 5-10 µl is introduced into a measuring cell, where for 2-5 seconds an inhomogeneous alternating electric field (IAEF) is formed with a frequency of ƒ 5⋅10⁴-10⁶ Hz and an average electric field strength E_o in the gap between the electrodes in the range of 10⁴-10⁶ V/m and a gradient of the square of the electric field strength 10¹¹-10¹³ [V²/m³]. A video recording of the behavior of cells in the measuring chamber between the electrodes is made and it is entered into a computer in a measuring and computing complex (MCC). Next, the parameters of erythrocytes are calculated:

х₁=D_av=(D₁+D₂+…+D_n)/n is the average diameter of the erythrocyte,

where D₁ is the diameter of the first cell;

D₂ - diameter of the second cell;

D_n is the diameter of the nth cell;

n is the number of cells;

is the rate of translational movement of the erythrocyte in an electric field,

where S is the distance traveled by the cell during t;

is polarizability,

where is the modulus of the square of the gradient of the electric field strength between the electrodes of the measuring cell;

x4=ω_p1=(ƒ_p) is the equilibrium frequency;

is the electrical conductivity of the erythrocyte,

where R_c is the resistance of the cell;

R_m - resistance of the medium;

is the generalized erythrocyte viscosity index,

where C_c is a generalized indicator of erythrocyte stiffness;

τ_p - duration of the probing radio pulse;

π is a constant value equal to 3.14;

r_c is the radius of the cell in the electric field;

x_m is the maximum amplitude of cell deformation;

is a generalized indicator of cell stiffness,

where α_c is the polarizability of the cell;

ε_O is the dielectric constant equal to 8.85⋅10^-12;

E is the electric field strength;

r_c is the radius of the cell in the electric field;

x_m is the amplitude of cell deformation;

is the maximum amplitude of the deformation of the cell,

where is the initial diameter of the cell, before the inclusion of the IAEF;

is the maximum diameter of the cell when the IAEF is turned on. Then the obtained data are compared with the corresponding values of the level of fecal calprotectin and erythrocyte indices determined for a group of patients conventionally healthy without pathologies. In the presence of 60% or more different parameters from the group of conventionally healthy subjects without pathologies and within the limits of the values indicated in Table 1 of the description, patients are diagnosed with active or inactive inflammatory bowel disease.

EFFECT: method makes it possible to increase the specificity and accuracy of the analysis of inflammatory bowel diseases at earlier stages with the determination of variants of its preclinical manifestations by selecting and measuring the most significant electrical and viscoelastic parameters of erythrocytes in combination with the determination of the level of fecal calprotectin.

1 cl, 4 dwg, 2 tbl, 2 ex