B2M and hydrops fetalis: Moreover, patients with high ferritin had higher levels of creatinine (p = 0.002), PCR (p = 0.03), β2M (p = 0.01), NLR (p = 0.02) and MLR (p = 0.006), and a statistical “trend” was also observed for high monocyte count and the HF group (p = 0.07) (Supplementary Figure S2A).