Method Description

Copeptin pro-arginine vasopressin (proAVP) is measured in this homogeneous automated immunofluorescent assay on the BRAHMS Kryptor Compact PLUS. The Kryptor Compact PLUS uses TRACE (time resolved amplified cryptate emission) technology based on a nonradioactive transfer of energy. This transfer occurs between 2 fluorescent tracers: the donor (europium cryptate) and the acceptor (XL707). In the Copeptin proAVP assay, a sheep polyclonal antibody against C-terminal proAVP is labeled with europium cryptate and a mouse monoclonal antibody against C-terminal proAVP is labeled with XL707. Copeptin is sandwiched between the 2 antibodies, bringing them into close proximity. When the antigen-antibody complex is excited with a nitrogen laser at 337 nm, some fluorescent energy is emitted at 620 nm and the rest is transferred to XL707. This energy is then emitted as fluorescence at 707 nm. A ratio of the energy emitted at 707 nm to that emitted at 620 nm (internal reference) is calculated for each sample. Signal intensity is proportional to the number of antigen-antibody complexes formed and, therefore, to antigen concentration.(Unpublished Mayo method)