NPPB and hydrops fetalis: NT-proBNP is the recommended initial test in patients suspected of HF, but the levels at which NT-proBNP is thought to make HF unlikely differ among guidelines (National Institute of Health and Clinical Excellence: 400 pg/mL vs European Society of Cardiology HF125 pg/mL).9 10 38 Thresholds for NT-proBNP are affected by patient characteristics/comorbid conditions and drug treatment and debated in HFpEF.39 40 An observational study reported that one in five patients with HFpEF may be missed if the higher cut-off value of 400 pg/mL is used.30