Fig. 2.

Raman spectra of erythrocytes from COVID-19 patients reveal significantly altered hemoglobin–associated vibrational modes compared to healthy donors. a Raman mean spectra of erythrocytes from healthy donors, COVID-19 patients, and convalescent patients. Dashed boxes indicate wave number ranges with marked changes of hemoglobin–associated vibrational modes. b Principal components analysis (PCA) was conducted on the Raman data. The scores of the PCA can distinctly discriminate the COVID-19 patients (green) from healthy (red) and convalescent patients (blue). c Loading blots of PC1 to PC3. These plots show, which parts of the Raman spectra are important for the distribution of the data in the scores plot. The higher a peak, the more important is it