Disialo-trisialo bridging of transferrin is due to increased branching and fucosylation of the carbohydrate moiety

► Samples with unresolved di- and trisialotransferrin on HPLC were collected. ► Three different glycoform patterns were identified. ► The di-tri bridging phenomenon was associated with altered transferrin glycosylation. ► Increased amount of triantennary and fucosylated N-glycans were found.