The amount of a CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 2 when measured in blood serum. The trait is level of CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 2 in blood serum (OBA_2044410, an Ontology of Biological Attributes id). Also known as: blood serum CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 2 amount.