The amount of a bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthase 1 when measured in blood serum. The trait is Ontology of Biological Attributes entry OBA_2042761 (level of bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthase 1 in blood serum). Also known as: blood serum bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthase 1 amount.