Diagnostic value of method for determining blood dielectric constant for detecting sensitization to penicillin G and ceftriaxone
The objective of the study - to determine the diagnostic value of dielectric parameters of whole blood samples in the presence of penicillin G and ceftriaxone of patients with chronic dermatoses with a history of antibiotic sensitization. Materials and methods. Fifteenth patients with allergic dermatoses, 10 patients with limited scleroderma with a history of antibiotic sensitization and 15 healthy donors (control group) were examined. Dielectric constant of the blood of intact samples (not loaded with antibiotics) and experimental samples (loaded with antibiotics) was determined by microwave dielectrometry. The change in the relative amount of free and bound water in the experimental blood samples in relation to the intact samples was evaluated. Blood samples were stabilized with 0,109 M solution of trisubstituted sodium citrate and incubated in the presence of ceftriaxone and penicillin G for 2 hours at 37 °C. The concentration of antibiotics was 250 μg/ml. Sensitization to ceftriaxone and penicillin G of patients was detected using allergological tests: leukocyte agglomeration reaction (RAL) and erythrocyte sedimentation rate (ESR). Results. The dielectric constant of intact and experimental blood samples from healthy donors did not significantly differ: ε’ = (1,97 ± 0,017) x 10-10 F/m and ε’ = (1,965 ± 0,019) x 10-10 F/m, respectively. A significant difference ε’ was recorded in intact and experimental samples of patients with various forms of dermatoses with a history of antibiotic sensitization, and it was more pronounced in patients with limited scleroderma: ε’ = (1,863 ± 0,011) x 10-10 F/m in the presence of penicillin G and ε’ = (1,903 ± 0,014) x 10-10 F/m in the presence of ceftriaxone. A more significant increase in the amount of bound water was in experimental blood samples loaded with penicillin G, compared with ceftriaxone. Perhaps this is due to the presence of a greater number of hydration binding sites in the complex «protein-metabolite of penicillin G». The correlation coefficient of the obtained data by two methods was - for penicillin G - ESR-dielectrometry (rs = +0,934), RAL-dielectrometry (rs = +0,883); for ceftriaxone - ESR-dielectrometry (rs = +0,917), RAL-dielectrometry (rs = +0,871). Conclusions. The possibility of using dielectric constant of blood in a clinic is shown as an additional screening test for determining sensitization to detect the development of allergic reaction to penicillin and cephalosporin antibiotics.