Thalassaemia can be diagnosed using a blood test. Further DNA testing may be needed so the exact type of thalassaemia can be determined.
Unlike other haematological conditions such as sickle cell anaemia, new-born babies aren't routinely screened for thalassaemia. There are two reasons for this:
- blood tests are usually unreliable during the first six months of life
- unlike sickle cell anaemia, thalassaemia doesn't present an immediate threat to a baby's life – babies born with sickle cell anaemia have a high risk of developing serious infections and need immediate treatment with antibiotics
If your baby starts to develop the symptoms of thalassaemia as they get older, a diagnosis can be confirmed using a blood test.
The purpose of antenatal screening (screening carried out during pregnancy) is to check for inherited disorders, such as sickle cell anaemia and thalassaemia, and to provide parents with the information they need to make informed decisions.
Pregnant women are routinely screened for the thalassaemia trait. If they test positive, their partner will also be offered the test. If both parents have the thalassaemia trait, there's a one in four chance their baby will have thalassaemia.
Further testing is also available to confirm whether your baby will definitely be born with thalassaemia. There are three methods of testing for this:
- chorionic villus sampling – a small sample of placenta (the organ that's attached to the womb lining during pregnancy) is removed and tested
- amniocentesis – a small sample of amniotic fluid is taken from inside the womb for testing
- foetal blood sampling – under local anaesthetic, a small sample of blood is taken from your baby's umbilical cord or from the umbilical vein as it passes through their liver
Being told that your baby will be born with thalassaemia can be traumatic and upsetting.
You'll be offered counselling to give you and your partner the opportunity to express your feelings and to ask questions about how the diagnosis may affect you.
The counsellor will tell you about the different options available to allow you to make an informed decision about how to proceed with the pregnancy.
Pre-implantation genetic diagnosis (PGD) is an option for couples who don't want to give birth to a child with thalassaemia but are unwilling to consider terminating a pregnancy.
PGD is similar to in-vitro fertilisation (IVF). IVF is a method of helping infertile couples conceive by surgically removing an egg from the woman's ovaries and fertilising it with the man's sperm in a laboratory.
As with IVF, PGD involves removing eggs from a woman's ovaries, which are fertilised using a sample of sperm taken from her partner. The fertilised embryo can be tested for thalassaemia. If the results are negative, the embryo can then be implanted into the woman's womb.
PGD is a fairly new procedure that's only available at a number of specialist thalassaemia centres. A list of national sickle cell and thalassaemia centres is available on the Brent Sickle Cell & Thalassaemia Centre website.