Fig. 1

Overview of study design and time points at which blood samples were collected in response to challenge tests for biomarker analysis. Twenty healthy male volunteers and 20 T2D subjects were given the PhenFlex test (PFT) drink or a glucose drink (OGTT) in randomized order on two different study days. The wash-out period between the two challenge tests was at least 2 days. On study days, blood samples were taken at t = 0 (≥ 10 h of fasting) and six time points (t = 0.5, t = 1, t = 2, t = 4, t = 6, and t = 8 h) after consumption of the challenge drinks for analysis of a total of 132 different metabolic markers