CST3 and hydrops fetalis: In a study of individuals without HF enrolled in the United Kingdom (UK) Biobank cohort, Nowak et al. reported that the addition of the cystatin C-based estimated glomerular filtration rate (cysC-eGFR) and the urine albumin-to-creatinine ratio to the ARIC study HF risk score led to a significant improvement in the risk discrimination ratio (ΔC = 0.019 (95% CI, 0.015–0.022)) [20].