The amount of a phosphatidylcholine O-16:0_16:1 when measured in blood serum. The trait is level of Phosphatidylcholine (O-16:0_16:1) in blood serum (OBA_2045112). Also known as: blood serum phosphatidylcholine O-16:0_16:1 amount, level of phosphatidylcholine O-16:0_16:1 in blood serum.