Sample Collection
±2
Venous blood samplings were scheduled on days 14 (±2) and 28 (±4) according to the study protocol of the underlying RCT, but had to be rescheduled until a clinical indication for blood sampling arose to avoid study-driven venous punctures for ethical reasons. Time deviation from milk samples were −5 to +1 days. EDTA blood was centrifuged to separate EDTA plasma within 30 min of venipuncture, with 50 µL plasma immediately frozen at −30 °C and stored at −80 °C until analysis.