Serum ferritin levels correlate with haemoglobin concentration: a report on 589 outpatients from a single centre.

Abstract

Haemochromatosis, a disease characterised by an increase in iron storage which may cause pathological changes1, is divided into primary or secondary forms. While primary (or genetic) haemochromatosis, the most common autosomal recessive disorder, is due in the majority of cases to mutations in the HFE gene, secondary haemochromatosis can have several causes including ineffective erythropoiesis and multiple red blood cell transfusions1,2. A number of studies have documented that subjects carrying mutations in the haemochoromatosis gene have significantly increased peripheral blood erythrocyte indices (haematocrit, haemoglobin and mean corpuscular haemoglobin concentrations), compared with wild-type individuals, thus suggesting an evolutionary sex-related protecting role against iron deficiency3–7. By contrast, no studies have so far analysed the relationship between serum ferritin, a widely accepted measurement of iron storage, and haemoglobin concentration. We, therefore, performed a retrospective analysis on the database of the Laboratory Information System of the Clinical Chemistry Institute of the University Hospital of Verona on outpatients referred by the general practitioner to our laboratory for routine blood testing. Between May 2004 and May 2007, 1,907 consecutive subjects underwent routine blood tests including measurement of serum ferritin levels and inflammatory indices (C-reactive protein) and blood cell count. After the exclusion of women, duplicate tests from the same person and individuals with abnormal inflammatory indices or low serum ferritin levels ( 350 μg/L, mean 658.4 ± 341.8 μg/L). The mean age and haemoglobin concentration were then compared between these two groups (Table I). Table I Characteristics of the 589 patients enrolled in the study There were statistically significant differences in age (36.3 ± 26.1 years in the first group versus 51.6 ± 16.4 years in the second group, p <0.0001) and haemoglobin concentration (14.4 ± 1.7 g/dL in the first group versus 15.5 ± 1.6 g/dL in the second, p < 0.0001). In conclusion, the results of our study document a positive correlation between serum ferritin level and haemoglobin concentration, thus confirming the previous data from studies on patients with primary iron overload. The different mean age between the two groups is also an interesting finding of our study and testifies that iron accumulation is an age-dependent process which happens regardless of the underlying cause.