APA Dictionary of Psychology

an acute-phase protein synthesized primarily by the liver in response to proinflammatory cytokines (especially interleukin-6). CRP circulates in blood plasma and is widely used as a clinical biomarker of systemic inflammation, with concentrations rising rapidly following infection, tissue injury, or inflammatory disease. CRP testing helps clinicians detect and monitor inflammatory conditions such as autoimmune disorders, inflammatory bowel disease, and some infections. High-sensitivity CRP (hs-CRP) assays can identify lower levels of chronic inflammation and are commonly used in cardiovascular risk assessment, as persistently elevated levels are associated with greater risk of atherosclerotic cardiovascular disease and, to a lesser extent, metabolic disorders such as type 2 diabetes. CRP levels may also be modestly elevated in the context of chronic psychological stress, depression, and other conditions linked to low-grade inflammation, though CRP is a nonspecific marker and must be interpreted alongside clinical findings and other tests.