The Anti-SGPG Autoantibodies ELISA from BUHLMANN is a semi-quantitative assay in which results are compared with a calibrator. In general, antibodies recognizing MAG react with a carbohydrate determinant that is also present on an acidic lipid, sulfoglucuronyl paragloboside. Anti-SGPG antibodies have a wider spectrum than anti-MAG antibodies do - some samples which are anti-SGPG positive are negative for anti-MAG antibodies. Therefore, samples should be tested for both antibodies.