GlycA is a composite biomarker that measures systemic inflammation by quantifying the glycosylation state of acute-phase proteins using nuclear magnetic resonance (NMR) technology. This test provides a stable measure of global inflammation status by integrating the protein levels and glycosylation states of several abundant acute-phase proteins including α1-acid glycoprotein, haptoglobin, α1-antitrypsin, and transferrin. Elevated GlycA levels indicate increased systemic inflammation and are associated with higher cardiovascular disease risk, both for initial events and recurrent cardiovascular events in patients with established coronary disease. The test is particularly valuable for cardiovascular risk assessment, as it has lower intra-individual variability than high-sensitivity C-reactive protein (hsCRP) and requires only one measurement for evaluation. GlycA can also help assess disease activity and cardiovascular risk in patients with rheumatoid arthritis or psoriasis.