level of Phosphatidylethanolamine (O-18:2_18:1) in blood serum (Ontology of Biological Attributes term OBA_2045149) is the amount of a Phosphatidylethanolamine (O-18:2_18:1) when measured in blood serum. Also known as: blood serum Phosphatidylethanolamine (O-18:2_18:1) amount.