A kit for screening for autoantibodies to a TSH receptor in a sample of body fluid obtained from a subject suspected of suffering from susceptible to, having or recovering from an autoimmune disease associated with an immune reaction to a TSH receptor, said kit comprising: (a) a full length TSH receptor, one or more epitopes of a TSH receptor comprising amino acid numbers 246-260 of a TSH receptor or a polypeptide comprising one or more of said epitopes of a TSH receptor; (b) one or more monoclonal or recombinant antibodies or fragments thereof to a TSH receptor, which monoclonal or recombinant antibody or fragment thereof comprises: an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 30 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 32 to provide an antibody binding site comprising both said heavy and light chains; or an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 34 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 36 to provide an antibody binding site comprising both said heavy and light chains; or an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 38 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 40 to provide an antibody binding site comprising both said heavy and light chains. (c) means for contacting said sample of body fluid from said subject; said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide; and said one or more monoclonal or recombinant antibodies or fragments thereof so as to permit said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide, to interact with either autoantibodies to a TSH receptor present in said sample, or said one or more monoclonal or recombinant antibodies or fragments thereof; and (d) means for monitoring the interaction of said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide with said autoantibodies to a TSH receptor present in said sample, thereby providing an indication of the presence of said autoantibodies in said sample. (a) a full length TSH receptor, one or more epitopes of a TSH receptor comprising amino acid numbers 246-260 of a TSH receptor or a polypeptide comprising one or more of said epitopes of a TSH receptor; (b) one or more monoclonal or recombinant antibodies or fragments thereof to a TSH receptor, which monoclonal or recombinant antibody or fragment thereof comprises: an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 30 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 32 to provide an antibody binding site comprising both said heavy and light chains; or an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 34 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 36 to provide an antibody binding site comprising both said heavy and light chains; or an antibody heavy chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 38 paired with an antibody light chain variable region encoded by a polynucleotide sequence for the variable region as shown in Figure 40 to provide an antibody binding site comprising both said heavy and light chains. (c) means for contacting said sample of body fluid from said subject; said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide; and said one or more monoclonal or recombinant antibodies or fragments thereof so as to permit said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide, to interact with either autoantibodies to a TSH receptor present in said sample, or said one or more monoclonal or recombinant antibodies or fragments thereof; and (d) means for monitoring the interaction of said TSH receptor, said one or more epitopes of a TSH receptor or said polypeptide with said autoantibodies to a TSH receptor present in said sample, thereby providing an indication of the presence of said autoantibodies in said sample.