We have for the past ten years been developing and exploring solid SERS substrates based on gold or silver coated nanopillars. Recently, we have, with kind support from the Danish Bio Innovation Institute and the European Innovation Council, focused on developing a SERS based platform for therapeutic drug monitoring (TDM). Here, we detect e.g., anti-cancer drugs  and antibiotics in patient blood samples, to monitor if the patient is receiving a correct dose within the therapeutic window. The vision is to be able to provide a tool for personalized treatment of critical diseases where correct dosing is essential and where a wrong dose can be lethal or cause severe side effects. We will share our recent findings and the prototype of a complete TDM device, with integrated sample pre-treatment using centrifugal microfluidics.