Diagnose glucagonoma. Glucagonoma may be present in three different syndromes. The first consists of a characteristic skin rash, necrolytic migratory erythema, diabetes mellitus or impaired glucose tolerance, weight loss, anemia, and venous thrombosis. This form usually shows very high glucagon levels, >1000 pg/mL. The second form is associated with severe diabetes, and the third form with multiple endocrine neoplasia syndrome. This form may have relatively lower glucagon levels.