Main diagnostic tools for assessment of iron overload
| Parameter | Advantages | Disadvantages |
| Transferrin saturation | Relatively non-invasive; inexpensive; routine laboratory assay | Values confounded by inflammation, liver function, and ascorbate status |
| Serum ferritin | Easy to assess; inexpensive; repeat measures are useful for monitoring chelation therapy; positive correlation with morbidity and mortality | Indirect measurement of iron burden; fluctuates in response to inflammation, abnormal liver function, metabolic deficiencies; serial measurement required |
| Liver biopsy | Direct measurement of LIC; validated reference standard; quantitative, specific and sensitive; allows for measurement of non-haem storage iron; provides information on liver histology/pathology; positive correlation with morbidity and mortality | Invasive, painful procedure associated with potentially serious complications; risk of sampling error, especially in patients with cirrhosis; requires skilled physicians and standardised laboratory techniques |
| LIC assessment by SQUID | Linear correlation with LIC assessed by biopsy; may be repeated frequently | Indirect measurement of LIC; limited availability; high cost; highly specialised equipment requires dedicated technician; not validated for LIC assessment and may underestimate levels |
| Quantitative iron assessment by MRI | The technique known as R2 (spin echo) MRI is a validated and standardised method for measuring LIC; cardiac iron levels can be rapidly and effectively assessed using a technique known as T2* (gradient echo) MRI, which is becoming the new standard method; potentially widely available; pathological status of liver and heart can be assessed in parallel | Indirect measurement of iron concentration in liver and heart; requires MRI imager with dedicated imaging method; methodology remains to be standardised and validated for assessment of cardiac iron |
LIC, liver iron concentration; SQUID, superconductive quantum interference device.