Guidance

2. Screening pathway

Updated 8 October 2024

Newborn blood spot (NBS) screening enables early identification, referral and treatment of babies with 9 rare but serious conditions. The programme helps to improve their health and prevent severe disability or even death. For each condition, the benefits of screening outweigh the risks.

NBS screening tests use a blood sample that is taken from a baby’s heel and spotted onto a special card containing the baby’s and mother’s details. The sample taker sends the blood spot card to a regional newborn screening laboratory for testing.

1. Eligibility

All babies under a year of age (up to but not including their first birthday) are eligible for NBS screening for all 9 conditions. This excludes the screening test for cystic fibrosis (CF), which is unreliable after 8 weeks of age.

If a baby under a year of age does not have documented results (or declines) for all 9 conditions, screening should be offered if the blood spot sample can be taken before they reach one year of age.

Only results documented in English are accepted (this includes translations). If screening was performed abroad and results are not documented in English, repeat screening should be offered. Screening should be offered for the untested conditions.

The 6 inherited metabolic diseases (IMDs) are always tested for together (if the baby has some IMD results missing the screening laboratory will screen the baby for all 6).

The newborn blood spot screening: movers in with no available records guidance provides more information.

2. Conditions

NBS screening programme offers screening for the following 9 conditions:

• sickle cell disease (SCD)
• cystic fibrosis (CF)
• congenital hypothyroidism (CHT)
• 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)

PKU, MCADD, MSUD, IVA, GA1 and HCU are inherited metabolic diseases (IMDs). The IMDs can cause severe illness and/or developmental problems, including serious learning disability. MCADD, MSUD and IVA can be immediately life threatening in the newborn period.

If not identified early, CHT can cause permanent, serious physical problems and learning disabilities.

For CF and SCD, although screening cannot prevent periods of illness, early detection can improve health.

NBS screening results are reported as not suspected (screen negative), suspected (screen positive) or carrier (SCD and CF only)

In any screening programme there are false positive results and false negative results. This means that a baby with a screen positive result may not have the condition. The likelihood that a baby with a screen positive result has the disorder varies with each condition.

3. Informed choice

NBS screening is recommended because it can improve health and prevent severe disability or even death.

Information is available to help parents make an informed choice about screening for their baby. Women receive screening tests for you and your baby at or before their booking appointment. The leaflet is available in a range of languages and contains a link to further information on NHS.UK.

A healthcare professional should discuss NBS screening in the third trimester of pregnancy to check parents’ understanding.

Parents must verbally agree to NBS screening. It is the healthcare professional’s responsibility to offer parents screening and record their decision in the baby’s and mother’s health records.

Parents must understand that they are agreeing to both testing and quality assurance processes that are an essential part of the screening programme. These include:

• completing the blood spot card and taking the sample
• testing the blood spot sample in a newborn screening laboratory
• additional testing of the same sample if the initial result is positive (may involve testing in another laboratory)
• contacting parents about the screening results – positive or negative or carrier (only for CF and SCD)
• referral to a specialist clinical team if the result is positive
• recording the screening results on laboratory and child health information systems, national newborn blood spot failsafe solution and sickle cell and thalassaemia newborn outcomes system
• retention and storage of residual blood spots for checking the screening results, monitoring and improving the screening programme

4. Declined screening

If parents decline screening, the healthcare professional must record their decision and reason (if stated) and notify other healthcare professionals (GP and health visitor) and the child health records department (CHRD)/child health information service (CHIS).

The blood spot card should be completed and sent to the laboratory with “decline” written on the card.

Parents should be given a letter that confirms their decision and details of whom to contact if they change their mind or would like further information. Refer to template letters for parents and healthcare professionals.

Parents can decline screening for SCD, CF and CHT individually but can only decline the 6 IMDs as a group. This is because of the way that the laboratory tests for the IMDs.

Further information on offering NBS screening and recording the parents’ decision is in the Guidelines for newborn blood spot sampling.

5. Day 5

The blood spot sample is taken on day 5 (day of birth is day 0). Day 5 is a practical balance between not screening too early (which can affect the accuracy of the CHT screening test used in England) and not screening too late, to make sure there is early referral and treatment if needed.

Following the guidelines on newborn blood spot sampling helps the sample taker to take a good quality sample. The sample taker sends the sample on the same day to the screening laboratory for analysis. Parents will receive ‘not suspected’ results by 6 weeks after the baby’s birth but suspected results as soon as they become available.

6. Residual blood spots

Residual blood spots are dried blood spots that are ‘left over’ after the laboratory punches (removes) several small discs from the sample to complete screening. The screening laboratory stores them for 5 years.

Laboratories use residual blood spots to check screening results, for testing equipment or methods, and for training and audit. It is a vital part of screening that helps to maintain high standards. If parents consent to screening, they cannot opt out of storage of their baby’s residual blood spots for these purposes.

6.1 Research uses

Residual blood spots have other potential uses, including health research. Some types of research are permitted without parents giving additional consent. This includes research that uses:

• anonymised samples (no details are linked to the blood spots)
• ‘de-identified’ samples (some information is linked to the blood spots but researchers are not able to identify the person that the sample comes from)

Sometimes researchers want to contact a child or family for research using the screening result or residual blood spot card. In this case, the researchers must contact parents to ask permission. This might be years after screening. When parents consent to screening, they must also be asked if they consent to any future contact about this type of research.

If parents do not agree to future research contact, this must be recorded in the mother and baby’s notes. It must also be recorded in the comments box on the blood spot card as ‘no research contact’.

A Research Ethics Committee and PHE’s Antenatal and Newborn Screening Research Advisory Committee must approve all research projects. The committee makes sure that the research is feasible, high quality and protects the safety of patients and the reputation of the screening programme. If samples and data are de-identified but not fully anonymised, then a researcher may also need to seek other regulatory and ethics approvals through the Health Research Authority - for example, support from the Confidential Advisory Group.

6.2 Offering NBS screening

The healthcare professional who offers NBS screening must inform parents about the storage and potential uses of residual blood spots. When offering NBS screening, make sure that parents understand:

• they are agreeing to processes that support the screening programme including storage of residual blood spots for 5 years
• residual blood spots can be used to check screening results, for testing equipment or methods, and for training and audit
• residual blood spots can also be used for health research that does not identify their baby
• they must be asked if they consent to future contact about research that could identify their baby

The text in ‘Screening tests for you and your baby’ can be used to help discuss residual blood spots with parents. NHS.UK also explains the potential uses using real examples.

Information can also be found in the code of practice for the retention and storage of residual newborn blood spots and the guidelines for newborn blood spot sampling.

7. Pre-transfusion / admission sample

On admission to a specialist hospital unit babies less than 5 days of age should have a single circle blood spot sample taken for the routine screening test for SCD, in case the baby subsequently needs a transfusion. This should be on a separate blood spot card marked ‘pre-transfusion’. More information is available in the guidelines for newborn blood spot sampling.

8. NHS number on the blood spot card

The ability to correctly identify and track the progress of all babies through the screening process is vital. It is mandatory to include the baby’s NHS number as a unique identifier on the blood spot card this includes babies who move into the area (movers in).

The NBS screening programme recommends use of a sticky label containing the NHS number in a barcoded and numerical format. Labels must be accurate and conform to standards set by the screening programme. Screening laboratories will contact maternity units if labels do not scan correctly.

9. Barcoded NHS number labels

Barcoded NHS number labels should be used to reduce the risk of an inaccurate NHS number on the blood spot card. The labels are generated when birth notification takes place. Parents receive them with the personal child health record on transfer home from hospital or before so that they are available for NBS screening.

The label contains the NHS number in the form of a barcode as well as printed numerals. The label also includes birth and demographic details. The sample taker applies the label to the blood spot card at the time of sampling.

Screening laboratories will scan the barcode into the laboratory information management system to uniquely identify the baby and track them through the system. This use of a unique identifier is fundamental for ensuring timely identification and treatment of screen positive babies.

There are standard requirements for generating and verifying barcoded NHS number labels.

9.1 Barcoded label verification

All maternity services must send a sample label to the NBS screening programme for quality verification. Providers must send a sample from each printer used. This ensures that the label can be read accurately by the laboratory’s barcode reader.

Contact the screening helpdesk for a submission form.

10. Transport

Completed blood spot cards must be sent to the screening laboratory on the same day (or, if not possible, within 24 hours of taking the sample). This is to make sure that the laboratory receives the sample in less than or equal to 3 working days and can process the sample as soon as possible.

Transport methods vary and include use of a first class prepaid/stamped address envelope or courier service. If a post box is used, it is important to make sure it has a daily collection (Monday to Saturday).

There should be no delay in sending the blood spot card to the laboratory. Cards should not be batched together for postage or introduce additional checking that causes delay.

Provider organisations should review transport methods regularly and have contingency plans in place for any exceptional circumstances (for example postal strikes, severe weather disruptions and at times of peak demand such as long bank holiday weekends).

11. Movers in

Offer screening to eligible movers in if the offer of screening can be made before (but not including) their first birthday, with the exception of CF which cannot be tested after 8 weeks of age. Screening should only be offered for the untested conditions. If any of the untested conditions are IMDs, and the parents accept screening, the screening laboratory will screen the baby for all 6 IMDs.

If parents accept screening, the blood spot sample must be taken no later than 14 calendar days after the baby’s first birthday. Samples should not be taken later than 14 calendar days after the baby’s first birthday as they will not be eligible for screening. If the process is to offer and take the sample on the same day, this can only be done before the baby’s first birthday.

If parents accept screening and the blood spot sample is taken, the screening laboratory will perform all processes until screening has been completed for all the untested conditions. This includes processing initial samples taken no later than 14 calendar days after the baby’s first birthday and requesting and processing repeat/further samples if required.

All screening results should be recorded on the child health information system less than or equal to 21 calendar days of notification of movement in.

Parents will receive ‘not suspected’ results by 6 weeks of notification of movement in but suspected results as soon as these become available.

The cut off at a year of age is a pragmatic decision, there are benefits of screening older infants and children, but these lessen with age.

12. More than 5 day working for laboratories

MCADD, IVA and MSUD can be immediately life threatening in the newborn period. Prompt identification and referral of screen positive babies helps to maximise health benefits and reduce the risk of permanent disability or death.

NBS screening laboratories should check and report screen positive results for MCADD, IVA and MSUD within 24 hours of being analysed successfully. This includes checking and reporting of results on Saturday (or Friday if this is a bank holiday).

13. Newborn blood spot failsafe solution

Babies can miss screening and blood spot samples can sometimes fail to reach screening laboratories or get delayed in transit. Babies affected by screened conditions can suffer serious harm by the time these failures are detected. In some cases they are not detected at all.

The impact on babies and parents, as well as the costs of treatment and care, is avoidable through use of the newborn blood spot failsafe solution (NBSFS). NBSFS is in use by all maternity units across England. It is an IT system that identifies babies, born in England, who have missed NBS screening. The system also records repeat requests and screening outcomes, to support failsafe processes.

The NBSFS user guide and operational level agreements for maternity users, child health records departments (CHRDs)/child health information services (CHISs) and screening laboratories provide more information about how to use NBSFS. There are also videos available to help users get the most from NBSFS.

The guidelines on handling patient information sets out how the NHS population screening programmes collect and process data safely and within the law.

The NBSFS user group:

• monitors the quality of the NBSFS
• represents and provides feedback from users of the NBSFS
• identifies and prioritises areas for development

The user group welcomes feedback from NBSFS users. Please return a feedback form to your local representative (see page 2 of the feedback form).

14. Ordering blood spot cards

NBS screening cards (and glassine envelopes) are available via the NHS Print Contract. Orders should be placed via the secure online ordering website.

For any assistance please contact either the contract management team or the Xerox customer contact Centre.

Independent midwives can order a minimum of 50 cards using the online ordering system (complete and return the registration form).

15. Standards and data

15.1 Programme standards

NBS screening programme standards assess the NBS screening process. The standards are a set of measures that have to be met to make sure screening is safe and effective.

All health care professionals involved in the NBS screening pathway have a part to play in meeting these standards.

For example, if the newborn blood spot card is not accurately completed it can delay screen positive babies accessing treatment. This can result in permanent brain damage or even death if the baby has MCADD, MSUD or IVA.

The NHS Sickle Cell and Thalassaemia (SCT) Screening Programme standards cover newborn blood spot screening for sickle cell disease.

15.2 Key performance indicators

Key performance indicators (KPIs) are a subset of standards. PHE Screening collects and reports data on KPIs quarterly. The NBS screening programme currently has 3 KPIs.

Maternity units submit KPI data about blood spot quality (avoidable repeat rate).

CHRDs/CHISs submit KPI data about to 2 aspects of coverage (the proportion of babies who are tested and receive a result).

15.3 Data collection and reporting

The programme collects data on the NBS standards from CHRDs/CHISs and screening laboratories and publishes an annual report. Providers must make sure data is accurate, timely and complete. This enables programme evaluation.

Designated clinical teams must report outcome data to the screening laboratory for each screen positive baby.

The programme also collects false negative screening data on CF, CHT and the IMDs. SCD data is collected by the SCT screening programme. This data shows how many babies with a condition were missed by the screening programme (known as ‘affected not detected’ cases).