The amount of a cytosolic endo-beta-N-acetylglucosaminidase when measured in blood serum. The trait is level of cytosolic endo-beta-N-acetylglucosaminidase in blood serum (Ontology of Biological Attributes entry OBA_2041477). Also known as: blood serum cytosolic endo-beta-N-acetylglucosaminidase amount.