ALB and COVID-19: COVID-19 severity correlated positively with the need for oxygen supply (r = 0.76, p < 0.001), community-acquired pneumonia (r = 0.59, p < 0.001), length of hospital stay (r = 0.52, p < 0.001), segmented neutrophils (r = 0.33, p = 0.005), and NLR (r = 0.35, p = 0.003), and correlated negatively with SpO2 (r = −0.52, p < 0.001), lymphocytes (r = −0.34, p = 0.003), eosinophils (r = −0.36, p = 0.002), monocytes (r = −0.24, p = 0.040), and albumin (r = −0.28, p = 0.017).