Ferritin is a protein that stores iron in the body and protects it from the toxic effects of free iron. Ferritin can be used as a biomarker in cerebrospinal fluid and is used in the diagnosis of aneurysmal subarachnoid hemorrhages[^1].

Clinical Relevance

The measurement of ferritin in cerebrospinal fluid is particularly used when imaging does not show a clear finding for a subarachnoid hemorrhage, but there still is a clinical suspicion of it. Therefore, the determination of ferritin is part of cerebrospinal fluid diagnostics for exclusion or confirmation diagnosis of aneurysmal subarachnoid hemorrhage.