The amount of a galactoside alpha-(1,2)-fucosyltransferase 1 when measured in blood. The trait is level of galactoside alpha-(1,2)-fucosyltransferase 1 in blood (Ontology of Biological Attributes identifier OBA_2051421). Also known as: blood galactoside alpha-(1,2)-fucosyltransferase 1 amount.