Every baby is offered newborn blood spot screening, also known as the heel prick test, ideally between 48 and 72 hours after the baby is born.
What is the blood spot test?
Newborn blood spot screening involves taking a blood sample to find out if your baby has 1 of 9 rare but serious health conditions.
The conditions tested for include:
- phenylketonuria (PKU)
- hypothyroidism
- cystic fibrosis
- congenital adrenal hyperplasia (CAH)
- Other rare conditions that affect metabolism
These conditions do not show any symptoms at birth and usually there is no family history.
It is very helpful to test for these conditions early, as treating them as soon as possible can prevent further health problems (complications).
Most babies won't have any of these conditions but, for the few who do, the benefits of screening are enormous.
Early treatment can improve their health, and prevent severe disability or even death.
What does the blood spot test involve?
Blood is taken by pricking the baby’s heel, a healthcare professional will prick their heel and collect 4 drops of blood on a special card.
Having the heel prick may cause brief discomfort to your newborn. You can ease any distress for your baby by cuddling and feeding them, and making sure they're warm and comfortable.
Occasionally, the sample may need to be taken when your baby is 6, 7 or 8 days old.
Sometimes a second blood spot sample is needed. The reason for this will be explained to you. It doesn't necessarily mean there's something wrong with your baby.
The test doesn't carry any known risks for your baby.
Does my baby have to have the blood spot test?
The blood spot test is not compulsory, but it's recommended because it could save your baby's life.
You can choose to have screening for sickle cell disease, cystic fibrosis or congenital hypothyroidism individually, but you can only choose to have screening for all 6 inherited metabolic diseases or none at all.
If you don't want your baby to be screened for any of these conditions, discuss it with your midwife.
You should be given information about the blood spot test and the diseases it screens for in advance so you can make an informed decision for your baby.
If you change your mind, babies can be screened up to the age of 12 months for all the conditions except cystic fibrosis. Cystic fibrosis can only be screened for up to 8 weeks of age.
If you have any concerns about the tests, speak to your midwife, health visitor or Obstetrician.
What do the results mean?
Most babies will have a normal result, which means it's unlikely that they have any of the conditions.
A small number of babies will screen positive for one of the conditions. This doesn't mean they have the condition, but they're more likely to have it. They'll be referred to a specialist for more tests.
It's important to know that screening isn't 100% certain. A baby with a negative screening result may later turn out to have the disease screened for. This is known as a false negative.
Babies with a positive result sometimes turn out not to have the disease – what's known as a false positive.
Occasionally, other medical conditions are picked up by blood spot test screening. For example, babies with beta thalassaemia major, a serious blood disease, will usually be detected. These babies also need to be referred for early treatment.