Does selling assayed plasma—which is used for calibration and quality control in medical analyses—fall under the ruling on selling blood?

Firstly: It is not permissible to sell "serum" (blood plasma) due to the Prophet's (peace be upon him) prohibition of the price of blood, which is Haram by consensus.

Secondly: The solution is to separate and assay the serum for a known fee, instead of selling it.

Thirdly: Whoever needs serum and cannot find it except for a price, it is permissible for him to pay money to obtain it, and the sin is upon the taker. It is permissible to give money as a gift or reward to encourage donation, not as a recompense.