There is an incredible demand for human blood. In the United States alone, a transfusion is required every two seconds. Over 41,000 one-pint donations are needed every single day. While as much as 38% of the American population is able to donate blood, only around 10% actually do, which isn’t enough to keep up with demand. However, the use of synthetic blood may change all of that.

Synthetic blood may seem like a fantasy from HBO’s True Blood, but a research team in Romania has had surprisingly encouraging results from the first trials of using blood manufactured in a laboratory. The blood is composed of expected ingredients like water, salt, and albumin, but it also contains proteins from an unlikely source: marine worms. The iron protein, hemerythrin, is responsible for oxygen transport and storage.

Hemerythrin has the added benefit of making the blood stress resistant, which has been a considerable challenge in other attempts to manufacture a synthetic blood alternative. Previous blood formulas could not stand up to stress factors and ended up turning toxic. Hemerythrin is the only protein to succeed on this front so far.

The trials were completed using mice, and will continue to do so until it has been exhaustively shown that the synthetic blood does not pose a risk for toxicity. Head researcher, Radu Silaghi-Dumitrescu, from Babes-Bolyai University speculates that it will be around two more years before the formula is ready for human testing. Human trials “represent an enormous risk” and Silaghi-Dumitrescu wants to ensure all safety concerns have been addressed beforehand.

Success in trials over the next two years will lead the team to publish their results and Silaghi-Dumitrescu has confirmed that he will seek a patent on the formula.

Earlier this year, a Scottish laboratory was granted permission to begin human trials for synthetic blood derived from adult stem cells.