The amount of a queuine tRNA-ribosyltransferase catalytic subunit 1 when measured in blood serum. The trait is Ontology of Biological Attributes entry OBA_2043137 (level of queuine tRNA-ribosyltransferase catalytic subunit 1 in blood serum). Also known as: blood serum queuine tRNA-ribosyltransferase catalytic subunit 1 amount.