Hyperferritinemia: causes and significance in a general hospital.

Objective: To elucidate conditions which cause elevation of the serum ferritin, extent of the elevation in each condition, and clinical relevance of hyperferritinemia in general practice.
Methods: We retrospectively studied medical records of all patients who had at least one serum ferritin measurement above 500 μg L ^-1 . Patients who had a marked elevation of the serum ferritin over 10,000 μg L ^-1 were studied separately.
Results: We studied 1394 patients to identify the etiologies of hyperferritinemia. Median serum ferritin level was 1024 μg L ^-1 and 49.2% had ferritin levels of 501-1000 μg L ^-1 . The most frequent cause of hyperferritinemia was non-human immunodeficiency virus infection followed by solid tumor, liver dysfunction, renal failure, and hematological malignancy. The distributions of the causes were different among groups stratified by the ferritin level. Forty-one percent had multiple causes and there was a tendency that the more underlying causes a patient had, the higher the ferritin level. Each condition led to a wide range of the ferritin level, and some patients could present with marked hyperferritinemia. Seventy percent of 111 patients with marked hyperferritinemia had multiple etiologies and a variety of diseases could lead to marked hyperferritinemia by themselves.
Discussion: Patients with hyperferritinemia frequently had multiple conditions. The level of the serum ferritin was determined by the underlying conditions to a certain extent; however, the variation was significant. While patients with marked hyperferritinemia mostly had multiple underlying causes, various diseases could cause hyperferritinemia by themselves.
Conclusion: Hyperferritinemia is associated with both etiology and the number of underlying causes.