Serum biomarker enables diagnosis and monitoring of idiopathic pulmonary arterial hypertension

Nature Medicine, Published online: 09 January 2026; doi:10.1038/s41591-025-04135-2 We have identified serum levels of extracellular domain of NOTCH3 (NOTCH3-ECD) as a biomarker that can reliably distinguish idiopathic pulmonary arterial hypertension from other forms of pulmonary hypertension and healthy controls. Our findings show that serum NOTCH3-ECD levels are as accurate as current standard-of-care clinical tests in predicting disease progression and mortality risk. Nature Medicine, Published online: 09 January 2026; doi:10.1038/s41591-025-04135-2 We have identified serum levels of extracellular domain of NOTCH3 (NOTCH3-ECD) as a biomarker that can reliably distinguish idiopathic pulmonary arterial hypertension from other forms of pulmonary hypertension and healthy controls. Our findings show that serum NOTCH3-ECD levels are as accurate as current standard-of-care clinical tests in predicting disease progression and mortality risk.