The amount of a leucine-rich repeat, immunoglobulin-like domain and transmembrane domain-containing protein 3 when measured in blood serum. The trait is level of leucine-rich repeat, immunoglobulin-like domain and transmembrane domain-containing protein 3 in blood serum (Ontology of Biological Attributes term OBA_2044515). Also known as: blood serum leucine-rich repeat, immunoglobulin-like domain and transmembrane domain-containing protein 3 amount.