Testing/Diagnosis

blood test tubesIf you think you might have haemochromatosis make an appointment with your Doctor.

Diagnosis of genetic haemochromatosis (GH) is often made late. This is dangerous because untreated iron overload leads to organ damage and other problems, much of which is irreversible. Any of the common symptoms – especially in combination – should lead your doctor to arrange tests that may confirm GH at the earliest opportunity.

Diagnosis is made through any or a combination of the following tests. You may hear references to genotyping, or molecular diagnosis, which are terms referring to definitive genetic testing results, or phenotyping, which is a term used when referring to analysis of the physical symptoms or traits of a genetic condition.

Transferrin saturation (TS)

TS is the ratio of two simple blood tests, which indicates iron accumulation. Serum iron is divided by total iron binding capacity (TIBC) to give the TS percentage. Normal average is 30% (slightly higher in men than women). If on two occasions this is over 50% in men or 45% in women, GH is very likely and your doctor should then measure serum ferritin.

Serum ferritin

This indicates the amount of iron stored in the body. Levels significantly over 300µg/l (micrograms per litre) in men and post menopausal women, and 200µg/l in women are further evidence of GH. It should be realised that in the early stages of iron accumulation, serum ferritin may be within the normal range and thus raised TS with a normal serum ferritin level does not rule out a diagnosis of GH.

Genetic testing

A simple genetic test for the HFE gene mutation is positive in over 95% of those affected. It will also identify family members at risk of loading iron.

Testing is using a blood sample from which DNA is extracted and analysed. More information about possible mutations of the HFE gene can be found on our frequently asked questions page.

Prior to genetic testing and on the delivery of results you may also be referred to a geneticist or genetic counsellor to discuss the implications for your family and the interpretation of results.

Liver biopsy and other liver tests

A small sample of the liver is removed using a biopsy needle, which shows whether tissue damage such as cirrhosis is present. This is often recommended when the serum ferritin reading is over 1000µg/l, there is evidence of abnormal liver function, or the HFE test is negative.

A form of magnetic resonance imaging (MRI) scan called FerriScan is coming into use as an alternative to liver biopsy but is only available at a few hospitals in the UK. Liver transient elastography (Fibroscan) is similar to an ultrasound scan and is more widely available. This test is being increasingly used to detect or exclude more severe forms of liver damage such as cirrhosis.

Other blood tests may also be ordered by your doctor or consultant to test liver function.

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