Blood Metal Profiles Measured by Laser-Induced Breakdown Spectroscopy and IgG Anti- 1 body Levels: Comparative Analysis in SARS-CoV-2 Patients and Healthy Controls

Characterizing host-pathogen interactions and immune responses to SARS-CoV-2 is essential for advancing diagnostic and therapeutic development. This study compares blood metal levels measured by laser-induced breakdown spectroscopy and Immunoglobulin G (IgG) antibody levels of plasma samples collected in 150 individuals aged 18–65. Forty-six of the samples were acquired from these individuals who have never been exposed to the SARS-CoV-2, 64 who have, and 40 were blind during the measurements analysis of the spectra. Our findings suggest that at the earliest measurable stage of SARS-CoV-2 infection, identified by the initial increase in IgG antibody levels, the sodium-to-potassium (Na/K) ratio may decrease by approximately a factor of two. This reduction remains stable as IgG levels continue to rise. In addition, while alterations in the levels of other blood metals are also observed during early infection, these are less pronounced and exhibit a lower diagnostic sensitivity compared to changes in Na/K. These results suggest that changes in blood metal ratios, particularly Na/K, may reflect underlying biochemical processes associated with COVID-19 infection and immune response.