Short-Term In Vitro Exposure of Human Blood to 5G Network Frequencies: Do Sex and Frequency Additionally Affect Erythrocyte Morphometry?

Various studies have shown that radiofrequency electromagnetic fields (RF-EMF) influence cell proliferation, gene expression, and membrane function, as well as the immune, hematopoietic, and reproductive systems. Medical personnel who handle blood samples or patients who use mobile devices may inadvertently expose specimens to RF-EMF, which could compromise sample integrity and skew diagnostic parameters, such as the complete blood counts. Similarly, the shelf life or functionality of blood‐derived therapeutic products, such as erythrocyte and platelet concentrates, could be reduced during manufacturing, storage, or handling. Of particular concern in transfusion medicine is the possibility that RF exposure enhances the generation of reactive oxygen species, which can damage erythrocyte membranes and diminish deformability, a critical attribute for passing through the microvasculature. This study examines the in vitro effects of mobile phone radiation at different frequencies on complete blood count parameters, erythrocyte morphometry, and platelet activation in human blood samples.

Blood was drawn from 30 healthy volunteers (15 women and 15 men; aged 25–40 years) at the University Hospital Zagreb on three occasions, each 14 days apart. For each donor, fresh whole‐blood samples were paired with unexposed controls obtained simultaneously. Four fresh whole-blood samples were obtained simultaneously from each donor: two experimental samples and two control samples. The samples were exposed to one of three radio frequencies (700 MHz, 2500 MHz, or 3500 MHz /5G) in an HCTEM chamber at room temperature for two hours at an electric field strength of 10 V/m. The controls were kept under identical conditions inside a metal enclosure made of the same material as the HCTEM chamber. Following exposure, a complete blood count was performed. Platelet activation was assessed by flow cytometry, and erythrocyte morphometry was analyzed by quantifying cytoplasmic dimensions (namely length, width, area, and contour) via image analysis.

Complete blood counts and platelet activation did not differ between the exposed samples and the controls. In contrast, significant, frequency‐ and sex‐dependent alterations in erythrocyte morphometry occurred after radiofrequency exposure. The most pronounced effects occurred at 700 MHz. Erythrocytes both from male and female showed significantly increased size, contour irregularity, and membrane roughness. Female cells demonstrated greater sensitivity to RF-EMF exposure. At 2500 MHz and 3500 MHz, significant morphometric differences versus the controls were observed only in female erythrocytes. These cells were characterized by a higher contour index and decreased rigidity and form factor. Overall, male erythrocytes exhibited increased membrane roughness, while female erythrocytes primarily enlarged and became more rounded. Cluster analysis of morphometric indicators identified two erythrocyte subpopulations: smaller, round cells with smooth membranes versus larger cells with rough membranes. RF-EMF exposure shifted the distribution toward the larger, rough‐membrane subpopulation, but only significantly at 700 MHz and 3500 MHz.

Short‐term exposure to mobile phone radiation at three distinct frequencies, including 5G (3500 MHz), caused significant erythrocyte enlargement, rounding, and increased membrane roughness. It remains unclear whether these changes are transient or reversible. Female erythrocytes, which are more deformable, were more adversely affected. The authors propose the hypothesis that RF-EMF exposure causes cytoskeletal damage with, resulting in altered membrane permeability and deformability. The observed shift toward a larger rough‐membrane subpopulation may indicate accelerated erythrocyte aging due to mobile phone radiation.

Editorial Note:

The study’s strengths include repeated sampling, paired controls, and duplicate analyses. However, the absence of sham-exposed controls is a limitation. A dosimetric assessment yielding a standardized SAR value rather than uniform field strength alone might have contributed to a better understanding of the correlations. In addition, referring to “5G mobile phone radiation” throughout is misleading because only the 3500 MHz frequency corresponds to current 5G bands. Finally, situating these findings within the broader literature is challenging due to the limited and heterogeneous data on RF effects. Nonetheless, given the potential clinical implications, the authors' hypotheses warrant serious consideration. (RH)