It’s relatively easy to draw blood from a patient with easy-to-access veins, but much harder for patients without visible or palpable veins, and particularly with emaciated patients. In those cases, staff might have to resort to using an ultrasound machine to see veins more clearly.

The blood-sampling robot just skips straight to that step, using built-in ultrasound tech to guide the placement of the needle. The complete system also includes a module to handle samples and a centrifuge-based blood analyzer.

With easy to access veins, the machine can successfully draw blood 97 percent of the time, and had an overall success rate of 87 percent for 31 participants, the researchers said. According to the report, clinicians fail between 27 and 60 percent of the time for patients with difficult-to-access veins, depending on the nature of the problem. As a Redditor pointed out, however, the machine seems to have a lower success rate than medical personnel for difficult-to-access veins, other than for emaciated folks.

The robot is still a prototype and researchers could potentially improve its success rate, though. It could one day be used in ambulances, besides and emergency rooms for procedures like IV catheterization, dialysis and placing arterial lines. “A device like ours could help clinicians get blood samples quickly, safely and reliably, preventing unnecessary complications and pain in patients from multiple needle insertion attempts,” said lead author Josh Leipheimer.

The team is keenly aware of safety concerns. The three-piece folding design makes it effectively impossible to trigger the needle by accident, and there are plans for a case that would prevent the button from touching anything until the shot is necessary.

EpiWear is still very young, to the point where it’s made of 3D-printed parts. The students plan to refine it, however, including a smaller, more refined look that would be more acceptable on a night out. They’re even considering adding watch functionality so that it does more than sit on your wrist in ordinary situations. Should it become a practical reality, you might not have to feel awkward about carrying a life-saving injection with you — and you’d never have to worry about leaving it behind.