B2M and hydrops fetalis: Adjusted mean differences (SE) in predialysis β2M concentration between LF and HF dialysis were not materially different in the various reuse quartiles: -8.29(0.99), -9.68(1.22), -6.73(1.06), -8.42(1.27) mg/dl for 0–6, 7–12, 12–17, >17 reuses respectively.