Commercial blot assays are advanced applications of immunoblotting or dot immunobinding methodologies for the detection of specific autoantibodies in autoimmune diseases. Line(Dot) blots in particular have cost-effectively optimized a sort of multiparametric assay for simultaneous determination of several autoantibody reactivities. Efficient and wide-spectrum potentialities of recombinant DNA technology and proteomics are fruitfully employed by manufacturers in order to obtain highly purified antigens or novel targets to be spotted on blot matrices thus continuously implementing their multianalytic platforms. At present most widely used commercial blot assays for the diagnosis of connective tissue diseases can detect autoantibodies to several Extractable Nuclear Antigens or myositis and/or scleroderma associated autoantigens. They actually represent an important step-forward in the methodological panorama designed for the autoimmunity laboratory. However continuous effort in order to validate and improve clinical reliability of commercially available blot assays should be carried out. In this short review, our preliminary contribution on the validation of a commercial line blot assay for the laboratory diagnosis of autoimmune myositis is briefly reported.