So you suspect mixed connective tissue disease (MCTD). Which tests to perform?
D000974:Antibodies, Antinuclear / Q000302:isolation & purification; D000941:Antigens / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D002467:Cell Nucleus / Q000276:immunology; D004247:DNA / Q000276:immunology; D003882:Dermatomyositis / Q000175:diagnosis; D003937:Diagnosis, Differential; D005455:Fluorescent Antibody Technique; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis; D008947:Mixed Connective Tissue Disease / Q000175:diagnosis* / Q000276:immunology; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000276:immunology; D012595:Scleroderma, Systemic / Q000175:diagnosis; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000974:Antibodies, Antinuclear; D000941:Antigens; D001324:Autoantigens; D004247:DNA; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human