Method Description

Squamous cell carcinoma antigen (SCCA) is measured by homogeneous automated immunofluorescent assay on the BRAHMS Kryptor Compact PLUS. The Kryptor Compact PLUS uses time resolved amplified cryptate emission (TRACE) technology based on a nonradioactive transfer of energy. This transfer occurs between two-fluorescent tracers: the donor (europium cryptate) and the acceptor (Alexa Fluor 647). In the SSCA assay, an anti-SCC monoclonal mouse antibody is labeled with europium cryptate, and an anti-SCC mouse monoclonal antibody is labeled with Alexa Fluor 647. SSCA is sandwiched between the two 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 Alexa Fluor 647. This energy is then emitted as fluorescence at 647 nm. A ratio of the energy emitted at 647 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intensity is proportional to the number of antigen-antibody complexes formed and, therefore, to antigen concentration.(Unpublished Mayo method)