TF and congenital disorder of glycosylation: Barroso et al. recently reported a capillary LC-ESI-MS method to identify CDG and to discriminate between various CDG-II types based on the relative abundance of signature ions.16) We report herein that the MALDI-MS of tryptic peptides derived from transferrin is a viable alternative to LC-ESI-MS, and the peptide masses can be useful for diagnosing CDG-I and -II serving as reliable biomarkers of CDG.