C-reactive protein is made by the liver in response to inflammatory signalling, and its level tracks how much inflammation is active in the body at the time of the draw. It is a general marker: it says that an inflammatory process is running, not where it sits or what drives it. High-sensitivity assays measure the same protein at the low end, where it describes long-standing low-grade inflammation.
No readings for this marker yet.
Raised CRP most often follows infection, injury, surgery or a flare of an inflammatory condition, and the largest rises usually accompany bacterial infection. Modest elevations are common with excess body weight, smoking and chronic inflammatory or cardiometabolic conditions. Low values simply indicate no measurable acute inflammation at that moment. Because CRP names no cause, an unexpected raised result is a reason to re-test once any acute episode has passed and to discuss it with a doctor.
CRP rises within hours of an inflammatory stimulus and falls quickly once it resolves, so timing relative to a recent illness, injury, dental work or vaccination changes the number; strenuous exercise, pregnancy and estrogen-containing medication also shift it. It is read together with erythrocyte sedimentation rate, which moves more slowly and lags behind it, and with fibrinogen. For cardiovascular risk the high-sensitivity result is usually taken when well, away from any acute illness.
Reference ranges are general adult values and depend on lab, assay, age and sex. For orientation, not diagnosis — discuss results with your doctor.