Fetal anomaly screening standards valid for data collected from 1 April 2022
Updated 8 October 2024
Applies to England
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FASP-S01: coverage: T21, T18, T13 screening
Description
The proportion of pregnant women eligible for combined screening for Down’s syndrome (T21), Edwards’ syndrome (T18) and Patau’s syndrome (T13) for whom a conclusive screening result is available at the day of report.
Rationale
To provide assurance that screening is offered to everyone who is eligible and each woman who chooses to accept screening has a conclusive screening result.
Definition
We collect data on eligible women, tested women and women who decline screening.
Eligible women is the number of pregnant women booked for antenatal care during the reporting period, excluding women who:
- miscarry between booking and testing
- opt for termination between booking and testing
- transfer out between booking and testing (do not have a result)
- transfer in with a crown rump length (CRL) less than or equal to 84.0mm (on or before 14 weeks plus 1 day) who have a result from a screening test performed elsewhere in the NHS in this pregnancy
- present to ultrasound with a CRL between 45.0mm and 84.0mm (at or after 11 weeks plus 2 days to before or at 14 weeks plus 1 day) where it was not technically possible to measure the nuchal translucency (NT)
- present to the service (either dating scan or booking) with a CRL greater than 84.0mm (after 14 weeks plus 1 day) - some women may book and are thought to be before 14 weeks plus 2 days by last menstrual period (LMP) but when scanned they are found to be at or after 14 weeks plus 2 days; these women can be excluded if there were no delays in the usual process of booking the dating scan
- have pregnancies of a higher order than twins (for example triplets)
- have a vanished twin where ultrasound shows there is a second pregnancy sac containing a non-viable fetus
Tested women is the number of eligible women for whom a completed screening result was available from the combined test (T21 and or joint T18 and T13) screening at the day of report.
The eligibility criteria for entry into the combined screening pathway is a baby’s CRL measurement between 45.0mm and 84.0mm. This is equal to 11 weeks plus 2 days to 14 weeks plus 1 day of pregnancy.
For women between at or after 13 weeks plus 1 day and before or at 14 weeks plus 1 day, every effort must be made to accommodate the offer of the combined test and they should be included in the eligible women. In cases where the service is unable to offer the combined test, these women can be excluded.
Women who decline is the number of eligible women who are offered screening and make a personal informed choice not to accept screening, including women who choose to have private screening and do not wish to have NHS screening.
Performance thresholds
Thresholds are not set for this standard. FASP supports personal informed choice for women. There is no intention to publish performance of this data by maternity service. This standard supports the safety of the screening pathway by enabling screening services to be assured that:
- all eligible women are offered the opportunity of screening
- women complete the screening pathway where the offer is accepted
Caveats
Women should not be excluded but should be accounted for in the commentary if:
- a condition is suspected or identified at the first scan that requires onward referral (for example, anencephaly)
- the NT is measured as greater than or equal to 3.5mm and the woman declines blood sampling for biochemical testing before referral for clinical assessment - FASP recommends biochemical testing should be completed where screening is accepted
Data collection and reporting
Data source: maternity service, ultrasound department and screening laboratory.
Responsible for data quality and completeness: maternity service.
Responsible for submission: maternity service.
Reported by: maternity service.
Published by: performance published at national level (England) and completeness of data published by maternity service.
This standard is also the key performance indicator FA3.
Reporting period
Quarterly: data to be collated between 2 and 3 months after each quarter-end.
Deadlines: 30 September (Q1), 31 December (Q2), 31 March (Q3), 30 June (Q4).
Review dates
Date standard introduced: April 2015.
Date standard updated: April 2022.
FASP-S02: coverage: 20-week screening scan
Description
The proportion of pregnant women eligible for the 20-week screening scan who are tested, leading to a conclusive result within the defined timescale.
Rationale
To provide assurance that screening is offered to everyone who is eligible and each woman who accepts screening has a conclusive screening result.
Definition
The optimal time for completing the screening scan is at 18 weeks plus 0 days to 20 weeks plus 6 day of pregnancy.
The scan can be completed by 23 weeks plus 0 days for women in any of the following circumstances.
1. When a repeat scan is needed because the image quality of the first scan is compromised by:
- maternal body mass index (BMI)
- uterine fibroids
- abdominal scarring
- baby/babies in a sub-optimal position
A single repeat scan must be offered and completed by 23 weeks plus 0 days. The woman can be rescanned on the same day and if the scan is still incomplete, a new appointment should be offered according to local guidelines.
2. Where the provider has a pathway in place to offer the 20-week screening scan between 18 weeks plus 0 days and 23 weeks plus 0 days, this pathway must:
- be agreed with public health commissioners and screening quality assurance service (SQAS)
- facilitate referrals for further investigations and options for pregnancy choices in a timely manner
Ongoing audit of practice must be in place to monitor timeliness of the screening pathway.
3. When women present to the service at or after 20 weeks plus 6 days and the ultrasound department can offer a scan appointment and complete screening by 23 weeks plus 0 days.
Numerator: number of eligible women for whom a completed screening result was available from the screening scan (18 weeks plus 0 days to 23 weeks plus 0 days of pregnancy) at the day of report.
Denominator: number of pregnant women booked for antenatal care during the reporting period, excluding women who:
- present to the service at or after 23 weeks plus 1 day (as they are not part of the eligible population for the screening programme)
- miscarry between booking and testing
- opt for termination between booking and testing
- transfer out between booking and testing (do not have a result)
- transfer in at before or at 23 weeks and 0 days who have a result from a screening test performed elsewhere in the NHS in this pregnancy
The 20-week screening scan can be completed between 18 weeks and 0 days and 23 weeks plus 0 days weeks of pregnancy. For women between at or after 22 weeks plus 0 days and before or at 23 weeks plus 0 days, every effort must be made to accommodate the offer of the screening scan and they should be included in the denominator. In cases where the service is unable to offer the screening scan, they can be excluded.
Women who decline is the number of eligible women who are offered screening and make a personal informed choice not to accept screening, including women who choose to have private screening and do not wish to have NHS screening.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Acceptable level: greater than or equal to 95.0%
Achievable level: greater than or equal to 99.0%
Caveats
None
Data collecting and reporting
Data source: maternity service and ultrasound department.
Responsible for data quality and completeness: maternity service.
Responsible for submission: maternity service.
Reported by: maternity service.
Published by: maternity service.
This standard is also the key performance indicator FA2.
Reporting period
Data to be collated quarterly, 2 quarters in arrears. Due to the potential lag time between early booking and ultrasound scanning, the complete cohort cannot be accounted for until 2 quarters later.
Deadlines: 31 December (Q1), 31 March (Q2), 30 June (Q3), 30 September (Q4).
Review dates
Date standard introduced: April 2015.
Date standard updated: April 2022.
FASP-S03: diagnosis or intervention: test turnaround time quantitative fluorescence-polymerase chain reaction (QF-PCR)
Description
The proportion of QF-PCR test results reported in on or before 3 calendar days of sample receipt.
Rationale
To enable timely reporting of QF-PCR test results to women so they can make personal informed choices.
Definition
Numerator: number of QF-PCR test results reported on or before 3 calendar days of sample receipt.
Denominator: number of samples received in the genomic laboratory in the reporting period where the indication for QF-PCR testing was:
- an unexpected finding on the 20-week screening scan
- a higher chance T21, T18, T13 screening result from the combined test or a higher chance T21 screening result from the quadruple test
The chance cut-off is set at 1 in 150 at term for the combined and quadruple tests. This means women with a result of greater than or equal to 1 in 150 (between 1 in 2 and 1 in 150) are in the higher chance group.
Date of sample receipt in the genomic laboratory is counted as day zero.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Acceptable level: greater than or equal to 90.0%
Achievable level: greater than or equal to 95.0%
Caveats
None
Data collection and reporting
Data source: genomic laboratories.
Responsible for data quality and completeness: genomic laboratories.
Responsible for submission: genomic laboratories
Reported by: genomic laboratories.
Published by: genomic laboratories.
Reporting period
Annually by 30 June.
Review dates
Date standard introduced: April 2015.
Date standard updated: April 2022.
FASP-S04: test: 20-week screening scan
Description
The proportion of babies with a confirmed diagnosis of one or more of the specified conditions detected on the 20-week screening scan.
This standard is reported in 6 parts:
- S04a – transposition of the great arteries (TGA)
- S04b – atrioventricular septal defect (AVSD)
- S04c – tetralogy of Fallot (TOF)
- S04d – hypoplastic left heart syndrome (HLHS)
- S04e – coarctation of aorta
- S04f – congenital diaphragmatic hernia (CDH)
Rationale
To improve antenatal identification of babies with the specified conditions and enable timely information, support and interventions, where appropriate.
Definition
Numerator: number of eligible babies who had a completed 20-week screening scan where the specified condition was suspected or confirmed.
Denominator: number of eligible babies where the woman did not decline the 20-week screening scan and have a confirmed diagnosis of one or more of the specified conditions in the reporting period.
Performance thresholds
| Standard | Condition | Acceptable threshold | Achievable threshold |
|---|---|---|---|
| S04a | Transposition of the great arteries (TGA) | greater than or equal to 70.0% | greater than or equal to 99.0% |
| S04b | Atrioventricular septal defect (AVSD) | greater than or equal to 50.0% | greater than or equal to 80.0% |
| S04c | Tetralogy of Fallot (TOF) | greater than or equal to 55.0% | greater than or equal to 85.0% |
| S04d | Hypoplastic left heart syndrome (HLHS) | greater than or equal to 80.0% | greater than or equal to 99.0% |
| S04e | Coarctation of aorta | (not set) | (not set) |
| S04f | Congenital diaphragmatic hernia (CDH) – left and right sided | greater than or equal to 60.0% | greater than or equal to 70.0% |
Caveats
None
Data collection and reporting
Data source: notifying organisations (multiple sources).
Responsible for data quality and completeness: notifying organisations.
Responsible for submission: National Congenital Anomaly and Rare Disease Registration Service.
Reported by: notifying organisations (multiple sources).
Published by: regions, England.
NCARDRS use a multiple data source approach to improve data completeness and case ascertainment.
Reporting period
Annually by 30 September for women who book with an estimated date of delivery within the previous financial year (1 April to 31 March).
Review dates
Date standard introduced: April 2015.
Date standard updated: April 2022.
FASP-S05: test: turnaround time T21, T18, T13 screening
Description
The proportion of screening test results reported on or before 3 working days of sample receipt.
Rationale
To enable timely reporting of screening test results to women so they can make personal informed choices.
Definition
Numerator: number of screening test results reported by the screening laboratory to the maternity service on or before 3 working days of sample receipt.
Denominator: number of T21, T18, T13 screening samples received in the screening laboratory in the reporting period excluding samples received:
- that are not fit for analysis and a repeat sample is requested
- with missing information required for calculating the result
Date of sample receipt in the laboratory is counted as day 1. Sample receipt is when the sample is recorded as received on the laboratory information management system.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Acceptable level: greater than or equal to 98.5%
Achievable level: greater than or equal to 99.5%
Caveats
None
Data collection and reporting
Data source: screening laboratory.
Responsible for data quality and completeness: screening laboratory.
Responsible for submission: screening laboratory.
Reported by: screening laboratory.
Published by: screening laboratory.
Reporting period
Annually by 30 June.
Review dates
Date standard introduced: April 2015.
Date standard last updated: April 2022.
FASP-S06: test: inadequate samples for T21, T18, T13 screening
Description
The proportion of inadequate samples received in the laboratory in the reporting period.
Rationale
Good quality samples with essential information should be obtained first time to prevent avoidable repeats or delays in reporting screening results. These can cause unnecessary anxiety and are a waste of resources.
Definition
Numerator: number of samples received in the laboratory that were inadequate due to at least one of the following criteria:
- Sample did not contain sufficient blood to perform all tests.
- Sample was not in the correct tube or was contaminated.
- Sample did not arrive at the laboratory as specified in the specimen transport and storage section of the FASP handbook.
- Sample was not taken at the correct time (for combined screening CRL between 45.0mm and 84.0mm, for quadruple screening head circumference (HC) greater than 101.0mm up to 20 weeks and zero days).
- Sample did not have all data fields completed, as listed on the KPI template, to enable identification of the woman, analysis and reporting of results, including samples where the result needed recalculating after reporting.
Denominator: number of samples for T21, T18, T13 screening received in the laboratory in the reporting period.
‘Sample’ is defined as a request form (paper and or electronic) and blood sample for T21, T18, T13 screening using the combined test or T21 screening using the quadruple test.
A sample can be tested for T21 only, T18 and T13 only, or all 3 conditions depending on the woman’s choice.
This standard measures all samples.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Combined test:
- Acceptable level: less than or equal to 5.0%
- Achievable level: to be set
Quadruple test:
- Acceptable level: less than or equal to 10.0%
- Achievable level: to be set
Caveats
None
Data collection and reporting
Data source: screening laboratory.
Responsible for data quality and completeness: maternity service.
Responsible for submission: screening laboratory.
Reported by: maternity service.
Published by: maternity service.
This standard is also the key performance indicator FA4.
Reporting period
Quarterly: collated between 2 and 3 months after the end of each quarter.
Deadlines: 30 September (Q1), 31 December (Q2), 31 March (Q3), 30 June (Q4).
Review dates
Date standard introduced: April 2020.
Date standard updated: April 2022.
FASP-S07: referral: timeliness to information and support (T21, T18, T13)
Description
The proportion of women with higher chance T21, T18, T13 screening results attending an appointment in ≤ 3 working days to discuss their results.
Rationale
To provide assurance that women with higher chance results are referred, and receive timely information, and interventions where appropriate.
Definition
Numerator: number of women with higher chance results attending an appointment in ≤ 3 working days to discuss their results.
Denominator: number of women for whom a higher chance result (from the combined or quadruple test) is received by the maternity service in the reporting period.
The date the maternity service receives the result is counted as day 1.
The chance cut-off is set at 1 in 150 at term for the combined and quadruple tests. This means women with a result of greater than or equal to 1 in 150 (between 1 in 2 and 1 in 150) are in the higher chance group. These women must be offered an appointment to discuss their results and the option of prenatal diagnosis. The appointment can be face to face or virtual depending on the woman’s choice.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Acceptable level: greater than or equal to 97.0%
Achievable level: greater than or equal to 99.0%
Caveats
None
Data collection and reporting
Data source: maternity service.
Responsible for data quality and completeness: maternity service.
Responsible for submission: maternity service.
Reported by: maternity service.
Published by: maternity service.
Reporting period
Annually by 30 June.
Review dates
Date standard introduced: April 2004.
Date standard updated: April 2022.
FASP-S08: referral: timeliness to intervention (20-week screening scan)
Description
The proportion of women where an unexpected finding is suspected or confirmed in the baby at the 20-week screening scan.
This standard is reported in 2 parts: S08a (local referrals) and S08b (tertiary referrals).
Rationale
To provide assurance that women with a suspected or confirmed unexpected finding are referred in a timely manner and receive timely intervention where appropriate.
Definition
This standard relates to the 11 physical conditions as defined by FASP (see the FASP information for parents.
S08a - local referrals
Numerator: number of women referred locally and seen on or before 3 working days of the screening scan.
Denominator: number of women who had a screening scan within the reporting period with an unexpected finding and were referred locally.
Local referral is defined as a referral within the same provider organisation (this includes a local fetal medicine service).
S08b - tertiary referrals
Numerator: number of women referred to a tertiary centre and seen on or before 5 working days of the screening scan.
Denominator: number of women who had a screening scan within the reporting period with an unexpected finding and were referred to a tertiary centre.
Tertiary referral is defined as a referral from one provider organisation to a fetal medicine service in another provider organisation.
Date of the completed screening scan is counted as day 1.
We calculate performance by dividing numerator by denominator and multiplying by 100 to give a percentage.
Performance thresholds
Acceptable level: greater than or equal to 85.0%
Achievable level: greater than or equal to 97.0%
Caveats
None
Data collection and reporting
Data source: maternity service, ultrasound department, tertiary centre.
Responsible for data quality and completeness: maternity service.
Responsible for submission: maternity service.
Reported by: maternity service.
Published by: maternity service.
Reporting period
Annually by 30 June.
Review dates
Date standard introduced: April 2015.
Date standard updated: April 2022.