serum immunoglobulin measurement serum antibody level 2013-01-08T18:25:02Z A measurement of the amount of an immunoglobulin molecule possessing a specific amino acid sequence that binds to a specific antigen, a substance introduced into an organism which initiates an immune response including the production of the very antibodies which bind to it in an effort to destroy it, in a specified sample of serum, the clear liquid that separates from blood after it has clotted completely, i.e. blood plasma from which fibrinogen has been removed. CMO:0001277 clinical_measurement_ontology jsmith blood antibody level