Quantification of the amount of platelet-activating factor in a sample. The trait is Experimental Factor Ontology term EFO_0801075 (platelet-activating factor measurement). Also known as: AGEPC (acetyl glyceryl ether phosphorylcholine) levels, PAF acether levels, PAF levels, [(2R)-2-acetyloxy-3-hexadecoxypropyl] 2-(trimethylazaniumyl)ethyl phosphate levels, platelet activating factor levels.