obese, are not considered as good candidates for this test. Unfortunately, the technique is very expensive, technologically demanding and is currently only available in five centres in Europe and North America. However, arrangements can be made for patients from other counties to visit SQUID centres abroad for assessment, should the treating physician consider it necessary. Another method for measuring iron load in the liver still under investigation is Magnetic Resonance Imaging (MRI), which also relies on the paramagnetic properties of iron. Liver iron concentrations derived by this method (MRI, T2*) show reasonable and consistent correlation with those obtained by chemical analysis of liver biopsy samples. The potential advantage of this technology is that MRI is more widely available. MRI has also been shown to be a useful tool in evaluating iron load in the heart.
Iron content in the urine Another - long-established -- method of estimating iron load is by measuring the iron content in urine over a 24hour period, in order to assess the efficacy of chelation therapy with DFO. However, the clinical significance of this test is limited by the wide day-to-day variations in the DFO-induced secretion of iron in the urine.
Complications associated with DFO and how these may be addressed Local skin reactions The most common localised reactions include itching, redness, swelling, lumps, soreness, pain and general discomfort. The following tips may help reduce such reactions: (i) Avoid inserting the needle near important blood vessels or nerves, to minimise the risk of damage and/or bleeding. (ii) Check that the DFO has been dissolved in the correct volume of water (5ml of water for 500mg of DFO). If necessary, add extra water to further dilute the solution. (iii) Change the site chosen for injection. The abdomen is often the best site. Some patients prefer to use their upper arm or thigh. However, because localised reac tions are likely to occur at any site over time, it is important to use different parts of the body. Over time, the long-term use of DFO may cause lumps to form around the injection site. This can be prevented by rotating sites or, in some but not all cases, by filling the plastic infusion tubing with a small amount of a chemical substance known as hyluronidase, before setting up the pump.
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