Fast turn around monitoring of Angiotensin I and II in blood. Plasma and Serum samples were digested with an HTA Protease in 20 minutes, spiked with SIL Angiotensin I and II and analyzed by targeted LC-MS. This preliminary data demonstrates that Angiotensin I and II can be rapidly measured and multiplexed with several proteins using the methodology. This methodology allows an unprecedent ability to monitor circulating biomarkers in almost real-time.