obsolete serum amyloid protein physiology trait OBSOLETE. Any measurable or observable characteristic related to the function of an acute-phase reaction protein that is a precursor to amyloid A protein; it is present in very high levels during acute inflammatory episodes, and is present in low concentrations in normal sera, but is found at higher concentrations in sera of older persons and in patients with amyloidosis. SAA protein physiology trait Serum Amyloid A Protein physiology trait Trait.ontology VT:0002486 true