Sickle-cell anaemia - Diagnosing and screening for sickle cell anaemia
- Introduction
- Symptoms of sickle cell anaemia
- Causes of sickle cell anaemia
- Diagnosing and screening for sickle cell anaemia
- Treating sickle cell anaemia
- Things you can do to help ease sickle cell anaemia
- Complications of sickle cell anaemia
- See what the doctor sees with Map of Medicine
Sickle cell anaemia can be diagnosed using a blood test to check for defective haemoglobin.
A small amount of defective haemoglobin would suggest that you have the sickle cell trait (you're a carrier of the sickle cell gene), but don't have sickle cell anaemia. A high level of defective haemoglobin would indicate that you have sickle cell anaemia.
Antenatal screening
The purpose of antenatal screening (screening carried out during pregnancy) is to check for inherited disorders, such as sickle cell anaemia, and to provide parents with the information they need to make informed decisions.
Antenatal screening for the sickle cell trait is available where the condition is most common, typically areas with large Afro-Caribbean communities. In parts of the country where sickle cell anaemia is uncommon, a questionnaire that focuses on family origin is used to assess the risk of sickle cell disorders.
Pregnant women are routinely screened for the sickle cell trait. If they test positive, their partner will also be offered the test. If both parents have the trait, there's a one in four chance that their baby will have sickle cell anaemia.
Further testing is available (if you want it) to confirm whether your baby will definitely be born with sickle cell anaemia. One method involves taking a sample of cells from the placenta (the organ that's attached to the womb lining during pregnancy). This test is called chorionic villus sampling (CVS).
Counselling
Being told your baby will be born with sickle cell anaemia can be upsetting, so you'll be offered counselling to allow you and your partner the opportunity to express your feelings and question how the diagnosis may affect you.
The counsellor will make you aware of the different options available, allowing you to make an informed decision about how to proceed with the pregnancy.
Pre-implantation genetic diagnosis
Pre-implantation genetic diagnosis (PIGD) is an option for couples who know they're both carriers of the sickle cell trait and who don't want to have a child with sickle cell anaemia.
PIGD is similar to in vitro fertilisation (IVF). IVF is a method of helping infertile couples to 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, PIGD involves removing eggs from a woman’s ovaries and fertilising them using sperm taken from her partner. The fertilised embryo can be tested for sickle cell anaemia. If the test results are negative, the embryo can be implanted into the woman’s womb.
As with other types of IVF there's no guarantee that a course of PIGD will lead to a successful pregnancy. Overall, following PIGD treatment, the chance of a couple having a baby born with sickle cell anaemia is around one in five.
PIGD is a relatively new procedure that's only available at a number of specialist sickle cell centres. A list of national sickle cell and thalassaemia centres in England is available on the website of the Brent Sickle Cell and Thalassaemia Centre.
In most cases you would need to pay for PIGD on a private basis. It can cost around £8,000 for a single course of treatment.
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