The amount of a mitogen-activated protein kinase kinase kinase kinase 5 (human) when measured in blood. The trait is amount of mitogen-activated protein kinase kinase kinase kinase 5 (human) in blood (OBA_2052236, an Ontology of Biological Attributes entry). Also known as: blood mitogen-activated protein kinase kinase kinase kinase 5 (human) amount.