Cost-effectiveness is paramount for any new medical technology. If pharmaceutical companies do not see a profit, new drugs will never see the light of day. And if insurance companies think a new treatment is more expensive than the old one, they will simply not pay. Take thrombosis, or blood clotting, which affects millions of people worldwide. Blood thinners, like coumarins, are amongst the most widely used drugs to prevent blood clotting. But getting dosage right is a very challenging problem and errors have led to hospitalisations. The need for accurate dosage testing is thus clear.