Glycomics is a new subspecialty in omics system research that offers significant potential in discovering next-generation biomarkers for disease susceptibility, drug target discovery, and precision medicine. Alternative IgG N-glycans have been reported in several common chronic diseases and suggested to have great potential in clinical applications (i.e., biomarkers for diagnosis and prediction of diseases). IgG N-glycans are widely characterized using the method of hydrophilic interaction chromatography (HILIC) ultra-performance liquid chromatography (UPLC). UPLC is a stable detection technology with good reproducibility and high relative quantitative accuracy. In addition, the structure of IgG N-glycan is clearly separated, and glycan composition and relative abundance in plasma are characterized.