Unexplained Serum Ferritin Elevations in Primary Care Patients with Elevated Serum Ferritin Concentrations and High Normal Transferrin Saturations.
Authors: Onyekwere Onyinye C. , Johnson Tiffany N. , Fadojutimi-Akinsiku Margaret , Dawkins Fitzroy , Gordeuk Victor 
Published: April 2020

Non-HFE primary iron overload exists in African Americans and other ethnic groups, but the prevalence and spectrum of clinical manifestations are not known. In the HEIRS (Hereditary Hemochromatosis and Iron Overload Screening) Study, participants were considered for further evaluation if the serum ferritin concentration was elevated and the transferrin saturation was more than 45% for women or 50% for men. We hypothesized that these screening criteria would miss a substantial number of African Americans and members of other ethnic groups with increased iron stores. In the process of screening 21,231 predominantly African-American and Hispanic primary care patients at the Howard University field center of the HEIRS Study, we identified 161 non-HFE-C282Y homozygotes ≥ 25 years of age with serum ferritin concentrations above the 97.5 percentile for the population (&gt;700 ng/ml for men and &gt;500 ng/ml for women) but transferrin saturations in the upper part of the normal range (35–50% for men and 30–45% for women). Of the 123 participants we were able to contact, 68 (55%) participated in a clinical evaluation, including 64 African Americans, three Hispanics and one Asian American with a mean ± SD age of 57 ± 13 years. Thirty-eight (56%) were females, 6 (9%) were HFE H63D heterozygotes and 2 (3%) were C282Y heterozygotes. Seven patients (10%) had normal serum ferritin concentration on repeat testing while 42 (62%) had potential reasons for elevated serum ferritin concentration other than a primary increase in body iron including (sequentially) multiple blood transfusions (&gt;10 lifetime; n = 4), abnormal liver function tests (hepatitis C positive or AST &gt;60 IU/L and AST&gt;ALT; n = 17), hemoglobin &lt; 10 g/dL men or 9 g/dL women (n = 1), elevated C-reactive protein with transferrin saturation not elevated (n = 17), and excessive alcohol use (n = 3). Nineteen patients did not have these explanations for increased serum ferritin concentration and were considered to have a possible primary iron-loading process (see Table).

One of the patients with unexplained elevated serum ferritin concentration (an African American) had a diagnostic liver biopsy showing 2-3+ hepatocellular iron and heavy iron deposition in Kupffer cells and is on phlebotomy therapy; the others have been advised to have diagnostic liver biopsy or quantitative phlebotomy. We conclude that there are substantial numbers of African Americans with elevated serum ferritin concentration and normal transferrin saturation who have transfusional iron overload or a probable primary increase in body iron stores.

Characteristics of 19 Patients with Unexplained Serum Ferritin Elevations No. (%) of Women 8 (42) Age inyears (mean ± SD) 63 ± 14 Race (African American:Hispanic:Asian) 16:2:1 Hemoglobin in g.dL (mean ± SD) Men 13.8 ±1.5 Hemoglobin in g.dL (mean ± SD) Women 12.9 ± 0.8 HFE mutations in no. (%) C282Y heterozygotes 0 (0) HFE mutations in no. (%) H63D heterozygotes 2 (11) Ferritin category in no. (%) &lt; 500 ng/ml 7 (37) Ferritin category in no. (%) 500–1000 ng/ml 9(57) Ferritin category in no. (%) 1000 ng/ml&gt; 3 (16)