The amount of a microtubule-associated protein RP/EB family member 3 when measured in blood serum. The trait is level of microtubule-associated protein RP/EB family member 3 in blood serum (OBA_2042298, an Ontology of Biological Attributes entry). Also known as: blood serum microtubule-associated protein RP/EB family member 3 amount.