For the validation cohort, the analytical platform consisted of a 1290 UHPLC-system (Agilent) connected on-line to a 6550 Q-ToF equipped with a JetStream source (Agilent). 5 µl of each sample were injected onto a Kinetex C18 100 × 2.1 mm column, 2.6 µ, 100 Å (Phenomenex) and the following mobile phases were used at a flow rate of 0.5 ml/min: H2O with 0.1% formic acid (A) and 3:1 acetonitrile:isopropanol with 0.1% formic acid (B). The linear gradient was 0 min, 5% B; 7 min, 95% B; 9 min, 95% B; 9.2 min, 5% B; 11 min, 5% B. MS data was collected in centroid mode between m/z 70-1700 using the following ESI settings: Gas Temp, 300; Gas Flow, 8; Nebulizer Pressure, 40; Sheet Gas Temp, 350; Sheet Gas Flow, 11; Vcap, 4000; Fragmentor, 100; Skimmer1, 45; OctapoleRFPeak, 750. The analysis procedure has also been described previously (Staubert et al. 2015; Lindahl et al. 2016).