The amount of a Arf-GAP with SH3 domain, ANK repeat and PH domain-containing protein 3 when measured in blood serum. The trait is level of Arf-GAP with SH3 domain, ANK repeat and PH domain-containing protein 3 in blood serum (OBA_2040690, an Ontology of Biological Attributes term). Also known as: blood serum Arf-GAP with SH3 domain, ANK repeat and PH domain-containing protein 3 amount.