Serum Ferritin and its Importance for SARS-CoV-2-Infected Patients.

BACKGROUND: Serum ferritin is an acute-phase protein whose level is increased in several inflammatory diseases. This review describes the structure and function of ferritin as well as its association with the prognosis of patients with COVID-19. METHODS: We searched MEDLINE/PubMed databases, Scopus, and Web of Science for prospective and review articles that examined ferritin and its association with COVID-19 severity. Based on all these articles and clinical experience, a review was constructed and full texts of the articles that were retrieved were accessed. RESULTS: All COVID-19 related studies conducted in 2020, which performed serum ferritin testing, clearly showed ferritin as a biomarker of COVID-19 severity in hospitalized patients. Ferritin levels in severe patients were significantly increased relative to those in non-severe patients (p < 0.001). Non-survivors had significantly higher ferritin levels than the survivors (p < 0.001). CONCLUSIONS: Determination of ferritin levels was specific and sensitive for early disease severity prediction in patients with COVID-19. Serum ferritin can also be used for predicting the response to COVID-19 vaccines.