Screening for Iron Overload Using Transferrin Saturation

Abstract

People with parenchymal iron overload exhibit an elevated serum iron concentration and a raised transferrin (TIBC) saturation early in the course of the disease. They can therefore be detected by simple laboratory tests before organ damage has occurred. In this study running for 2 months, 10512 samples from approximately 8750 patients and blood donors were examined in a county hospital in Central Sweden. Abnormal TIBC saturation (>70%) was found in 1.7% of the samples. This abnormality was caused by physiological fluctuations in serum iron in 44%, liver disease in 22%, blood disorder in 10%, iron therapy in 10.5% and parenchymal iron overload in 11.5%. The diagnosis of iron overload was confirmed by measuring the serum ferritin concentration and by performing the desferrioxamine test, liver biopsy, quantitative phlebotomy and family studies including HLA typing. We found a prevalence of iron overload of 0.24%. This figure is almost certainly too low because some affected patients were probably lost because of TIBC desaturation induced by inflammatory conditions.

Prevalence of Hemochromatosis in Finland

“…The screening limit for serum ferritin used in our study is rather high for women but even higher values are recommended for men (18). In a recent study serum fenitin of homozygotes of hemochromatosis, with a few exceptions, exceeded the level used in our study (9).…”

“…The combination of these two methods is very efficient in identifying the hemochromatosis cases (18,19). However, as in other studies (9,11,20) these tests in combination also give a fairly large number of false positives, although the number of false negatives is extremely small. Most of the false positive men in our study consumed considerable amounts of alcohol (40-60 g/day) or showed some findings related to heavy alcohol consumption.…”

“…The prevalence rate estimate in our study is not very far from the rate (100/100000) obtained from southern Sweden (11). The much higher prevalence rates (240-500/100000) also reported (8,9) could have resulted from selection of study populations or clustering of the disease and use of more liberal criteria for hemochromatosis, and cannot be considered applicable to the Finnish population.…”

HFE codon 63/282 (H63D/C282Y) dimorphism in German patients with genetic hemochromatosis

“…We observed the Same percentage of homozygous patients with hemochromatosis as in other northern European populations (33,36). This is most likely due to the variation in the frequency of the ancestral haplotype for hemochromatosis among the different study populations, and may be regarded as an indication of the northern European origin of this mutation (4,8,(43)(44)(45). Recent reports analyzing the distribution of the C282Y mutation in populations other than European support this hypothesis since the Tyr-282 substitution is very rare in the studied individuals (46,47).…”

Effect of Iron Chelation Therapy on Glucose Metabolism in Non-Transfusion-Dependent Thalassaemia

“…We enrolled 10 adolescents and young adults with serum ferritin >300 ng/ml. Transferrin saturation >70% could be used as an additional criteria for iron overload [20]. The discrepancy of iron status determined by serum ferritin, transferrin saturation and hepatic MRI examination was shown in some patients.…”