Mo. Rev. Stat. § 431.069

The procurement, processing, distribution or use of whole blood, plasma, blood products, blood derivatives and other human tissues, including but not limited to corneas, bones, hearts or other organs for the purpose of injecting, transfusing or transplanting any of them into the human body is declared to be, for all purposes, the rendition of a service by every person, firm, or corporation participating therein and, whether or not any remuneration is paid therefor, is declared not to be a sale of such whole blood, plasma, blood products, blood derivatives or other tissues, bones or organs for any purpose subsequent to enactment of this section. It is further declared that any implied warranties of merchantability and fitness for a particular purpose shall not be applicable as to a defect that cannot be detected or removed by reasonable use of scientific procedures or techniques. Nothing herein shall relieve any person, firm or corporation from negligence.