Cystic Fibrosis Screening Workflow and Follow Up Flashcards
What is the typical workflow for a CF newborn screening?
1) . Firday - Newborn screening lab will send a batch of samples (approximately 4-15 samples per week). Set up 4 mutation screen on a Friday.
2) . Monday/Tuesday - Run it out for pyrosequencing on a monday. Report on Monday. Put any samples where 1 or 2 mutations identified will go on to the CFEU2 extended panel.
3) . Wednesday - Report extended panel.
Working to tight deadlines and has to work every time each week. Important that all the parts of the screening process get done in a timely fashion and keep it robustly going.
Give an overview of the newborn blood spot screening pathway.
1) . Maternity services are taking the samples from babies and sending them into the lab.
2) . Sent to the screening labs including genetics.
3) . For positive cases need to liaise with specialist teams to get affected individuals on to treatment as quickly as possible.
4) . Primary care health visitor systems give out normal results.
5) . All the results coming out need to be collated by the child health records department.
Huge amount of machinery goes in to trying to get the coverage for the screening programme as complete as possible - making sure people who move into an area from places that didn’t do screening get picked up etc, making sure everyone is screened.
Describe clinical follow-up for CF newborn screening.
- Screening laboratory as communication hub.
- Each newborn screening centre will have some form of clinical liaison service - someone who links up the lab with clinical service - may be a screening nurse specialist, biochemist, CF regional centre, other.
1) . CF Not Suspected:
- Inform parents via health visitor in standard new born screening results.
- If had very high first IRT and need a second IRT is is important that they are seen soon after that as you have raised the family’s stress levels.
2) . CF Suspected:
- Refer within 24 hours to a regional CF centre.
- Referral to clinical genetics.
3) . Probable Carrier:
- Contact within 24hrs of 2nd IRT result.
- Low risk of being affected, or future children affected.
- Offer referral to CF specialist and Clinical Genetics.
Describe follow-up that is given when newborn screening result is CF Not Suspected.
1) . CF Not Suspected:
- Inform parents via health visitor in standard new born screening results.
- If had very high first IRT and need a second IRT is is important that they are seen soon after that as you have raised the family’s stress levels.
Describe follow-up that is given when newborn screening result is CF Suspected.
2) . CF Suspected:
- Refer within 24 hours to a regional CF centre.
- Referral to clinical genetics.
Describe follow-up that is given when newborn screening result is Probable CF Carrier.
3) . Probable Carrier:
- Contact within 24hrs of 2nd IRT result.
- Low risk of being affected, or future children affected.
- Offer referral to CF specialist and Clinical Genetics.
Are deltaF508 heterozugous individuals with a raised first IRT and normal 2nd IRT at increased risk of having an undetected second mutation?
- Study in 2000 looked at individuals who were deltaF508 heterozygotes with a raised 1st IRT and normal 2nd ITR.
- 23% were to have a 2nd mutation, particularly those with high normal IRT values.
- Many of these would be detected under the current strategy.
- Mainly (but not all) mild mutations.
- Shows that there is a correlation between types of CF mutation and IRT levels - severe mutation with mild second mutation can lead to a normal 2nd IRT test level.
Thinking points:
- Screening vs diagnostic testing
- Comparing screening programmes (e.g. CF vs MCADD)
- How are they different?
- Why are they different?
- How good are the tests?
- Where does genetics help?
- Where does genetics harm?
- Screening protocol vs diagnostic protocol
