Patent ID: 8883517

Claim:
A method of detecting a target autoantibody in a sample, comprising the steps of: a. contacting the sample with a small molecule fluorophore-labelled target protein autoantigen that specifically binds to the target autoantibody, wherein the contacting comprises diffusion of the target autoantibody and the small molecule fluorophore-labelled target protein autoantigen through a gel to reach equivalent concentrations at a particular location in the gel to form an immunoprecipitate of the target autoantibody and the small molecule fluorophore-labelled target protein autoantigen; and b. detecting the presence of the target autoantibody bound to the small molecule fluorophore-labelled target protein autoantigen, wherein the small molecule fluorophore-labelled target protein autoantigen comprises a nuclear autoantigen selected from the group consisting of Jo-1 antigen, Ro60 SSA antigen, La SSB antigen, Sm antigen, Sm/RNP complex antigen, and Scl-70 antigen.