A search for nonthermal effects of 434 MHz microwave radiation on whole human blood

Whole human blood was subjected to a microwave environment at 434 MHz for 6 hr with external electric fields corresponding to free space power densities up to 598 mW cm-2 and the levels of hemoglobin, sodium, and potassium in the plasma were monitored. Under geometrical conditions in which the field strength within the samples was unknown, measurements indicated increased red cell membrane fragility following irradiation. It was not possible to exclude localized heating as an explanation of this effect. However, with a known and reasonably uniform electric field distribution within spherical specimens, increased membrane fragility was not observed. We are therefore unable to confirm previously reported results which indicate a nonthermal deleterious effect of microwave radiation on erythrocytes.