The amount of a alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 5 when measured in blood serum. The trait is Ontology of Biological Attributes entry OBA_2043679 (level of alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 5 in blood serum). Also known as: blood serum alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 5 amount.