Liver iron concentration (LIC) accurately predicts total body iron stores
- when possible, it should be measured annually in patients undergoing regular transfusion therapy
- normal LIC values are up to 1.8 mg Fe/g dry weight, with levels of up to 7 mg/g dry weight seen in carriers of genetic hemochromatosis without apparent adverse effects
- several studies have linked very high LIC (> 15 mg/g dry weight) to worsening prognosis liver fibrosis progression and liver function abnormalities
- likely that very high liver iron concentrations are associated with high plasma non-transferrin bound iron (NTBI) because the liver is the main organ for removing free iron from plasma
- NTBI is damaging to the organs that are also affected by iron deposition
Liver biopsy provides a direct measurement of LIC, being quantitative, specific, and sensitive
- biopsy is an invasive procedure - however in experienced hands it has a low complication rate
- inadequate sample size (< 1 mg/g dry weight or < 4 mg wet weight or < 2.5 cm core length) or uneven distribution of iron, particularly in the presence of cirrhosis, may give misleading results
- LIC can also be measured accurately by superconducting quantum interference device
- results correlate well with chemical estimation of LIC unless fibrosis is present
Reference:
- Hoffbrand AV et al. How I treat transfusional iron overload. Blood. 2012 Nov 1;120(18):3657-69.
- Kushner JP, Porter JP, Olivieri NF. Secondary iron overload. Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program 2001;2001(1):47-61.