The amount of a Phosphatidylethanolamine (18:0_0:0) when measured in blood serum. The trait is level of Phosphatidylethanolamine (18:0_0:0) in blood serum (OBA_2045138, an Ontology of Biological Attributes entry). Also known as: blood serum Phosphatidylethanolamine (18:0_0:0) amount.