The fact that third parties may be involved in all steps of the chain from donation and procurement to distribution in most Member States highlights the importance that needs to be given to the written agreements established by tissue establishments and their verification by the national competent authorities.
Kuna enamikus liikmesriikides võivad kolmandad isikud osaleda kõigil etappidel loovutamisest ja hankimisest kuni jaotamiseni, on eriti tähtsad koepankade koostatud kirjalikud lepingud ning nende kontrollimine riiklike pädevate asutuste poolt.