Evaluation of serum ferritin level in patients with fever of unknown origin

Abstract

Background Diagnosis of the cause of fever of unknown origin (FUO) is a great challenge. Serum ferritin may be a useful index for differentiating between infectious and noninfectious causes of FUO (malignant disease or collagen disease). In this respect, serum ferritin has the advantage of decreasing the number of unnecessary tests and helping to exclude infectious disease. Objective This study aimed to evaluate serum ferritin levels among patients suffering from FUO. Methods A comparison was made between infectious, noninfectious, and undiagnosed cases of FUO as regards serum ferritin level using an in-vitro enzyme-linked immunosorbent assay. Results The most common causes of FUO were infectious diseases (120/300, 40%), followed by noninfectious diseases such as malignant (61/300, 20.4%) and autoimmune causes (49/300, 16.3%). Undiagnosed cases constituted 70/300 (23.3%). The mean serum ferritin level in the infectious group, noninfectious group, and undiagnosed group was 99.25±49.58, 1098.94±284.54, and 112.40±183.23, respectively, with highly significant difference between infectious and noninfectious causes of FUO (P Conclusion High serum ferritin level (>559 ng/ml) helps in differentiation between infectious and noninfectious causes of FUO. In undiagnosed cases of FUO we must direct our thinking to infectious diseases.