Praise be to Allah.
This is regarded as selling blood, and selling blood is haraam according to scholarly consensus.
It says in Fataawa al-Lajnah al-‘Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Ifta’ (13/71):
It is not permissible to sell blood, because of the report in Saheeh al-Bukhaari from Abu Juhayfah who said that he bought a cupper (as a slave) and ordered that his equipment be broken. He was asked about that and he said: The Messenger of Allaah (peace and blessings of Allaah be upon him) forbade the price of blood.
Al-Haafiz said in al-Fath: What is meant is that it is haraam to sell blood just as it is haraam to sell dead meat and pork, and it is haraam according to scholarly consensus, i.e., to sell blood and take its price. End quote.
It says in al-Mawsoo’ah al-Fiqhiyyah (9/148):
It is haraam and, the contract is invalid, to sell “blood poured forth” because Allaah says (interpretation of the meaning): “… or blood poured forth (by slaughtering or the like),” [al-An’aam 6:145]. Ibn al-Mundhir and al-Shawkaani stated that there was consensus among the scholars on the prohibition on selling blood. End quote.