Guidance

Blood spot

Updated 18 December 2024

This information was created on behalf of the NHS. In this information, the word ‘we’ refers to the NHS service that provides screening.

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This short video explains blood spot screening in newborn babies.

Newborn blood spot video

Blood spot screening is recommended by the NHS.

1. Purpose of screening

To find out if your baby has any of 9 rare but serious health conditions.

Early treatment can improve your baby’s health and prevent severe disability or even death. If you, the baby’s father, or a family member already has one of these conditions, please tell your health professional straight away.

2. About these conditions

2.1 Sickle cell disease

About 1 in 2,800 babies born in the UK has a sickle cell disease (SCD). These are serious, inherited blood diseases. They affect haemoglobin, a part of the blood that carries oxygen around the body. Babies who have SCD will need specialist care throughout their lives.

People with SCD can have attacks of severe pain, get serious, life-threatening infections and are usually anaemic (their bodies have difficulty carrying oxygen). Babies with SCD can receive early treatment, including vaccinations and antibiotics, which, along with support from their parents, will help prevent serious illness and allow them to live a healthier life.

2.2 Cystic fibrosis

About 1 in 2,500 babies born in the UK has cystic fibrosis (CF). This inherited condition affects the digestion and lungs. Babies with CF may not gain weight well and frequently have chest infections. Babies with CF can be treated early with a high-energy diet, medicines and physiotherapy. Although children with CF may still become very ill, early treatment can help them live longer, healthier lives.

2.3 Congenital hypothyroidism

About 1 in 2,000 babies born in the UK has congenital hypothyroidism (CHT). Babies with CHT do not have enough of the hormone thyroxine. Without thyroxine babies do not grow properly and they can develop permanent serious physical problems and learning disabilities.

Babies with CHT can be treated early with thyroxine tablets and this will allow them to develop normally.

2.4 Inherited metabolic diseases

It is important to let your health professional know if you have a family history of a metabolic condition. Babies are screened for 6 inherited metabolic diseases (IMDs).

These are:

• phenylketonuria (PKU)
• medium-chain acyl-CoA dehydrogenase deficiency (MCADD)
• maple syrup urine disease (MSUD)
• isovaleric acidaemia (IVA)
• glutaric aciduria type 1 (GA1)
• homocystinuria (pyridoxine unresponsive) (HCU)

About 1 in 10,000 babies born in the UK has PKU or MCADD. The other conditions are rarer, occurring in 1 in 150,000 babies to 1 in 300,000 babies.

Babies with these inherited conditions cannot process certain substances in their food. Without treatment babies with some of these conditions can become suddenly and seriously ill. The symptoms of the conditions are different; some may be life threatening or lead to severe developmental problems.

They can all be treated by a carefully managed diet, which is different for each condition and may include additional medicines.

3. The screening test

When your baby is 5 days old the health professional will prick your baby’s heel using a special device to collect some drops of blood onto a card. Occasionally this may be later than 5 days. The heel prick may be uncomfortable and your baby may cry. You can help by making sure your baby is warm and comfortable, and by cuddling and feeding them.

Sometimes, a second blood spot sample is required later on. If so, the reason will be explained. It does not necessarily mean there is something wrong with your baby.

4. Safety of the test

There are no known risks to your baby associated with having the test.

5. Screening is your choice

Screening your baby for all these conditions is recommended because it could save your baby’s life but it is not compulsory. You can choose to have screening for SCD, CF or CHT individually but can only choose to have screening for all 6 IMDs or none at all. If you do not want your baby screened for any of the conditions or have any concerns about the test, please talk to your midwife.

Early screening is best as treatment can be started as soon as possible if needed. But if you choose not to have screening, your baby can have the test later if you change your mind. Babies can be screened up to 12 months of age for all the conditions except CF (only up to 8 weeks of age).

6. Possible results

Most babies will have normal results indicating that it is unlikely that they have any of the conditions. A small number of babies will screen positive for one of the conditions. This does not mean they have the condition but they are more likely to have it. They will be referred to a specialist for further tests.

Screening for cystic fibrosis finds some babies who may be genetic carriers of the condition. These babies may need further testing. Screening does not detect all carriers.

Occasionally, other medical conditions might be identified through these screening tests. For example, babies with beta thalassaemia major (a serious blood disease) will usually be detected. These children also need to be referred for lifelong treatment and care.

Screening for sickle cell disease also finds babies who are genetic carriers of these or other red blood cell diseases. Carriers are healthy although they can experience some problems in situations where their bodies might not get enough oxygen, for example, if they are having an anaesthetic.

7. Getting my results

You should receive the results from a health professional by the time your baby is 6 weeks old. The results should be recorded in your baby’s personal child health record (‘red book’). Please keep this safe and bring it with you to any further appointments. You will be contacted sooner if there is thought to be any problem with your baby.

8. My baby’s blood spot card and data after screening

After screening blood spot cards are stored for at least 5 years and may be used:

• to check the result or for other tests recommended by your doctor
• to improve the screening programme
• for research to help improve the health of babies and their families in the UK (this will not identify your baby and you will not be contacted)

In addition, there is a small chance that researchers may want to invite you or your child to take part in information gathering linked to the newborn blood spot screening programme. Researchers undertaking any additional studies would explain what is being done and you would then be asked if you wish to take part in that study. Please let your midwife know if you do not want to be contacted to discuss taking part in any additional information gathering.

All use of the blood spots is governed by the code of practice. Any research will have been approved by an independent research ethics committee.

Find more information and details of support groups on NHS.UK.