GlycA (NMR composite inflammation marker)

GlycA is a composite nuclear magnetic resonance (NMR) spectroscopy signal arising predominantly from N-acetyl methyl groups on acute-phase glycoproteins — primarily α1-acid glycoprotein, α1-antitrypsin, haptoglobin, α1-antichymotrypsin, and transferrin — and reflects the integrated concentration and glycosylation state of these inflammatory proteins. Because it integrates across multiple acute-phase reactants simultaneously, GlycA has lower within-person variability than hs-CRP and may better capture chronic low-grade systemic inflammation rather than acute fluctuations. Population studies associate higher GlycA with incident cardiovascular disease, type 2 diabetes, non-alcoholic fatty liver disease, cancer, and all-cause mortality, with some evidence that it predicts these outcomes independently of and complementary to hs-CRP. GlycA is currently a research-grade marker not routinely available in clinical laboratories and is most often reported as part of NMR lipoprotein panels.