Ferritin cannot be read as iron status while CRP is elevated

Ferritin is a positive acute-phase reactant: it rises with inflammation independently of how much iron is stored in the reticuloendothelial system. When CRP is elevated, a ferritin result reflects both iron stores and the active inflammatory response, with no physiological way to separate them from that single number. Guidance from the BRINDA project established regression-based corrections to adjust ferritin for concurrent CRP and AGP. The clinically crucial direction is the reassuring one: a ferritin sitting in the normal range during inflammation can mask true iron deficiency, because the acute-phase surge has pushed it up from a depleted baseline.

That iron stores are adequate (inflammation falsely elevates ferritin into the "normal" range). That iron overload is present (inflammation drives the elevation, not necessarily excess iron). That the ferritin laboratory result is inaccurate — the assay accurately measured circulating ferritin protein, but the concentration cannot be interpreted as iron status alone.

Read ferritin alongside transferrin saturation (TSAT), which is far less sensitive to acute-phase fluctuations. If iron status is the clinical question, retest ferritin once hs-CRP has returned below 3 mg/L.