The amount of a inactive tyrosine-protein kinase transmembrane receptor ROR1 (human) when measured in blood. The trait is amount of inactive tyrosine-protein kinase transmembrane receptor ROR1 (human) in blood (OBA_2052048, an Ontology of Biological Attributes entry). Also known as: blood inactive tyrosine-protein kinase transmembrane receptor ROR1 (human) amount.