Guidance

Newborn blood spot: managing positive results from cystic fibrosis screening

Updated 26 May 2021

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This publication is available at https://www.gov.uk/government/publications/clinical-referral-national-standard-protocol-for-cystic-fibrosis/newborn-blood-spot-managing-positive-results-from-cystic-fibrosis-screening

The NHS Newborn Blood Spot (NBS) Screening Programme aims to refer all screen positive babies to diagnostic and clinical care in line with national guidelines and standards.

Cystic fibrosis (CF) occurs when the cystic fibrosis transmembrane conductance regulator (CFTR) protein is either not made correctly, or not made at all.

This publication presents guidelines for managing babies who have a screening result of ‘CF suspected’. It also presents guidelines for ‘probable carrier, low likelihood of CF’ or ‘CF not suspected’ results following a second blood spot taken after an inconclusive result on the first sample.

The publication also presents guidelines on evaluating and managing babies with an unclear diagnosis after CF NBS screening. These are ‘CF screen positive, inconclusive diagnosis (CFSPID)’ cases. See A European consensus for the evaluation and management of infants with an equivocal diagnosis following newborn screening for cystic fibrosis and Cystic fibrosis screen positive, inconclusive diagnosis (CFSPID): A new designation and management recommendations for infants with an inconclusive diagnosis following newborn screening for more information.

1. Two CFTR mutations detected on the first blood spot sample – CF suspected

1.1 Responsibilities

Screening laboratory

The screening laboratory should:

  • refer the baby immediately to a designated person, or deputy, at the regional CF centre (this is the centre that covers the baby’s address on the blood spot card)
  • report the result by phone and in writing to the regional CF centre using the template letter
  • use the template letter to inform the baby’s GP of the positive screening result

It is essential that the GP understands that the result has been communicated directly to the regional CF centre that will make contact with the family. The letter to the GP is for information only.

Regional CF centre

The regional CF centre (and network CF clinics) should:

  • process the result promptly (perform the diagnostic assessment within 5 working days of receiving the result)
  • contact a local CF clinic if the clinic can provide the appropriate clinical and sweat test expertise (a local CF clinic is a recognised smaller clinic that works as part of a network with the regional CF centre at the hub of that network)
  • contact the baby’s primary care team (including their GP) to:
    • inform them of the screening result and plan contact with the family to give the result
    • ask if there are any relevant circumstances to be aware of
    • arrange a joint visit if possible

Primary care team

The primary care team (GP) should:

  • contact the regional CF centre if they have concerns about the family or queries about the screening result

1.2 Interaction with the family

There are a number of effective models for giving the screening result to the family. These models depend partly on local healthcare resources and organisations.

Regardless of the model adopted, several evidence-based principles should be applied.

Parents need to be contacted as soon as possible if their baby has a ‘CF suspected’ result. This enables them to start treatment as soon as this can be arranged. When arranging contact with the family, make sure that the diagnostic assessment can be offered the following day.

Inform the family by phone that the result will be discussed later that day. This enables the family to organise for more than one family member to be present. This should be an initial structured phonecall by a healthcare professional with appropriate experience and support to give bad news.

The positive CF screening result is usually given at a home visit but sometimes it can be given in a second structured phonecall alone. Either way, it should be done by a healthcare professional with knowledge of screening and CF, for example a CF clinical nurse specialist, screening link health visitor, screening nurse specialist or paediatrician. In all cases, a joint visit with the family health visitor with both parents present is optimal. See Parents’ experiences of receiving the initial positive newborn screening (NBS) result for cystic fibrosis and sickle cell disease for more information.

You must provide the parents with:

You should give the screening result to the family in the afternoon and offer parents or carers an appointment for the diagnostic assessment with the CF team the following morning.

At the first meeting with the family, emphasise that this is a positive CF screening result and further tests are needed to confirm the result. Explain that their baby does not need any urgent treatment now. They will receive advice about treatment from the specialist CF team over the next few days.

Give the family contact details about the appointment.

The result should be recorded in the personal child health record and in the baby’s notes. This will enable other healthcare professionals to access the results.

1.3 Diagnostic assessment visit

The diagnostic assessment should be undertaken by the CF team in a regional CF centre. In some circumstances the assessment may be in a CF clinic (a smaller network clinic that partners the regional CF centre). The CF clinic must have a team with the necessary experience to make and give a diagnosis, including an accredited sweat test service.

A sweat test is essential and should occur at the diagnostic assessment visit.

Give the result of the sweat test to the family as soon as it is available, preferably on the same day.

If a sweat test is not undertaken at the diagnostic assessment, or insufficient sweat is collected, organise repeat CFTR gene analysis at the diagnostic assessment. This can be undertaken on a blood sample or buccal (mouth) swab.

A sweat test is required for all babies and should include measurement of sweat chloride. See Guidelines for the performance of the sweat test for the investigation of cystic fibrosis in the UK 2nd version: an evidence based guideline for more information. If unsuccessful at the first visit, repeat the sweat test at a later stage.

The diagnostic assessment should include a clinical assessment of the baby.

If concerned about progress, start appropriate treatment even if sweat test or confirmatory genetic results do not confirm the diagnosis at that point. Babies in this situation have a ‘presumptive’ diagnosis of CF. Organise definitive confirmation of the diagnosis for these babies at the next clinical visit (within 2 weeks).

1.4 Early management and reporting outcomes

At the initial discussion, explain the NBS screening programme and the genetic nature of CF to parents or carers. Also give a basic explanation of how CF is likely to affect the baby.

It may not be appropriate for the family to spend time with all members of the CF team at the diagnostic assessment visit. Arrange for the CF team to visit the family over the next few days, or for the family to return to the regional CF centre or CF clinic.

A CF nurse specialist should be available to give advice and support to the parents. Give the parents written information about CF (including a link to the CF Trust’s parent information pack.

Introduce treatment regimens in a stepwise and timely manner, as deemed appropriate by the CF team.

If the baby has respiratory symptoms or malnutrition, or if there is family anxiety, it may be appropriate to admit the baby to initiate treatment more promptly.

Communicate the outcome of the first appointment and diagnostic tests to the newborn screening laboratory, GP and family health visitor.

Complete and return the Cystic fibrosis screening: CF suspected follow-up form to the newborn screening laboratory within 24 hours of assessment.

The data in the form will be de-identified and reported to the NHS NBS Screening Programme (Public Health England) as part of the annual data collection process to enable programme evaluation. For babies with a presumptive CF diagnosis, it is essential to forward the results of definitive testing to the laboratory, which will, in turn, update the NHS NBS Screening Programme.

Explore the benefits of, and encourage, registration of the baby on the UK CF Registry (with the parents’ written consent).

2. One CFTR mutation detected and raised second IRT – CF suspected

Immunoreactive trypsin (IRT) is used to screen for CF in newborn babies

For babies with this screening result, follow the guidance in part 1 and advice below.

When contacting the families of babies with this screening result, note the family will have raised anxiety levels because a second blood spot sample has been collected. They should have been told the reason for the repeat and when to expect the result. Information on the second blood spot sample is available for healthcare professionals and parents.

Inform the family of the CF suspected result promptly. Ideally this is within 24 hours of the laboratory obtaining the second IRT result if the diagnostic appointment can be arranged for the next day. Delays in confirming results and starting treatment can only add to parents’ anxiety.

3. No CFTR mutation detected but very high (≥ 99.9th centile) first IRT and raised second IRT – CF suspected

For babies with this screening result, follow the guidance in part 1 and advice below.

When contacting the families of babies with this screening result, note that the family will have raised anxiety levels because a second blood spot sample has been collected. They should have been told the reason for the repeat and when to expect the result. Information on the second blood spot sample is available for healthcare professionals and parents.

Inform the family of the CF suspected result promptly. Ideally this is within 24 hours of the laboratory obtaining the second IRT result if the diagnostic appointment can be arranged for the next day. Delays in confirming results and starting treatment can only add to parents’ anxiety.

4. One CFTR mutation detected and normal second IRT – probable carrier, low likelihood of CF

When contacting the families of babies with this screening result, note that the family will have raised anxiety levels because a second blood spot sample has been collected. They should have been told the reason for the repeat and when to expect the result. Information on the second blood spot sample is available for healthcare professionals and parents.

Inform the family of the CF suspected result promptly. Ideally this is within 24 hours of the laboratory obtaining the second IRT result.

Where possible, the screening laboratory should have a screening nurse specialist who contacts the family health visitor – or preferably a designated health visitor if there is an appointed lead health visitor for giving screening results to families – by phone and confirms in writing.

The screening laboratory:

4.1 Home visit and further support

The designated health visitor or alternate (who must be trained for the purpose) will visit the family to inform them of the result and give them the Your baby carries the cystic fibrosis gene information

Giving results over the phone is not satisfactory. Parents will have questions about their baby’s results and may also require access to reliable sources of further information and support.

If the family is concerned about the genetic implications of the result, they should discuss this with their GP. If necessary, the GP should refer the family to a clinical genetics centre.

Carriers can pass on the CF gene to their children, so it is important parents tell their child later in life that they are a carrier of the CF gene.

It is unlikely that any future children of the parents will have CF. However, it is possible that both parents are carriers of the CF gene. When both parents are carriers, all future children have a 1 in 4 chance of developing CF. They can find out if they are both carriers by asking their GP for an appointment with a clinical genetics centre.

Tell parents that occasionally there are uncommon alterations of the CF gene that are not recognised by the screening test and therefore there is a small chance that the child will have CF. They should contact their health visitor or GP if they have any concerns about their child’s health.

If the GP or family are concerned that the baby has symptoms of CF (poor weight gain, recurrent chest infections, rectal prolapse, nasal polyps), the baby should be referred to a regional CF centre.

Record the result in the personal child health record and in the baby’s notes. This will enable other healthcare professionals to access the results.

4.2 Follow-up

The healthcare professional who gives the carrier result to the family should complete and return the Cystic fibrosis screening: carrier of CF gene follow-up form to the newborn screening laboratory within 24 hours of the visit.

The data in the form will be de-identified and reported to the NHS NBS Screening Programme as part of the annual data collection process to enable programme evaluation.

5. No CFTR mutation detected, very high first IRT (≥ 99.9th centile) but normal second IRT – CF not suspected

When contacting the families of babies with this screening result, note the family will have raised anxiety levels because a second blood spot sample has been collected. They should have been told the reason for the repeat and when to expect the result. Information on the second blood spot sample is available for healthcare professionals and parents.

Inform the family of the CF not suspected result promptly. Ideally this is within 24 hours of the laboratory obtaining the second IRT result.

Where possible, the screening laboratory should have a screening nurse specialist who contacts the family health visitor or midwife by phone and confirm in writing.

The family health visitor or midwife will contact the family to inform them of the result.

6. Cystic fibrosis screen positive, inconclusive diagnosis (CFSPID)

Babies with this designation are babies with either:

  • a normal sweat chloride (<30 mmol/L) and 2 CFTR mutations, at least one of which has unclear phenotypic consequences or
  • an intermediate sweat chloride (30-59 mmol/L) and one or no CFTR mutations

6.1 Diagnosis

Confirmatory diagnostic tests

Babies with an unclear diagnosis after CF newborn screening are designated as CF screen positive, inconclusive diagnosis (CFSPID).

These babies require further diagnostic assessment.

A regional CF centre should be involved in this assessment.

Undertake subsequent sweat testing in an accredited laboratory with considerable experience of this procedure.

See A European consensus for the evaluation and management of infants with an equivocal diagnosis following newborn screening for cystic fibrosis and Cystic fibrosis screen positive, inconclusive diagnosis (CFSPID): A new designation and management recommendations for infants with an inconclusive diagnosis following newborn screening for more information.

After the diagnosis

Manage babies with a CFSPID designation as per the European CF Society (ECFS) guidance.

6.2 Reporting outcome

Communicate the outcome of the first appointment and diagnostic tests to the newborn screening laboratory, GP and family health visitor.

Complete and return the Cystic fibrosis screening: CF suspected follow-up form to the newborn screening laboratory as soon as follow-up results are available.

The data in the form will be de-identified and reported to the NHS NBS Screening Programme as part of the annual data collection process to enable programme evaluation.

7. Supporting information and letter templates

7.1 Taking a second blood spot sample for CF screening

See:

7.2 Managing ‘CF suspected’ screening results

See:

7.3 Managing ‘probable carrier, low likelihood of CF’ results

See:

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