Public Health England
Public Health England (PHE) commissions the Downs syndrome screening quality assurance support service (DQASS) to support the NHS fetal anomaly screening programme (FASP).
Purpose
The main aim of DQASS is to monitor and support the quality and effectiveness of Downs syndrome (T21), Edwards syndrome (T18) and Pataus syndrome (T13) screening in England.
DQASS provides feedback and support to laboratories, sonographers, the Screening Quality Assurance Service (SQAS) and to the FASP. The analyses provided by DQASS are used to improve the performance of the screening programme through feedback on all aspects of the test to laboratories, ultrasound departments and commercial suppliers.
The software used to calculate the T21 and/or T18 and T13 chance result from the biochemical and ultrasound markers is complex and best provided and supported by commercial suppliers. The screening programme has developed a specification for the chance result(s) calculation software for laboratories in England. Software used in screening laboratories must meet the requirements of this specification.
How DQASS works
DQASS works on a rolling audit of screening test data on a 6-monthly cycle. The statistical analyses monitor the screening process at various levels: from the overall standardised screen positive rate (SPR) at the top level, to specific adjustments for ethnicity, smoking and other factors applied to individual biochemical markers. Through meta-analyses, DQASS provides information on effects of factors such as smoking that is used to improve screening performance.
The FASP service specification requires all screening laboratories providing NHS screening to participate in DQASS. The service is provided to screening laboratories and individual ultrasound practitioners across England.
The screening support sonographer
The FASP recommends the provider has a screening support sonographer (SSS) and a deputy SSS with administrative support. These roles oversee the implementation, delivery and monitoring of the ultrasound aspects of the service. The SSS and deputy must actively participate in the DQASS process including submission of a minimum of 25 paired measurements on a 6-monthly basis.
The SSS should:
- follow FASP requirements as specified in the FASP handbook and by DQASS
- attend provider and commissioner led antenatal and newborn (ANNB) screening programme boards to represent the ultrasound service, and take the DQASS laboratory and ultrasound summary reports to these meetings
- put in place an on-going education and training programme for ultrasound practitioners
- undertake departmental review of ultrasound images including a log of dates that the image review was performed (this is required as evidence for SQAS)
- keep an accurate and up-to-date database of ultrasound practitioners and associated identity codes and inform DQASS:
- and the screening laboratory when a new ultrasound practitioner starts, or existing practitioners leave the provider and if known, their new place of work
- if any of their ultrasound practitioners work at other sites
- of new trainees to generate a unique identity code
- of the accuracy of DQASS/Fetal Medicine Foundation (FMF) identity codes and of any changes before the 6-monthly data submission
- of any omissions or errors in the DQASS reports (detailed ultrasound report for each individual ultrasound practitioner or ultrasound department summary report for each ultrasound provider) so an updated report can be issued if appropriate
- monitor throughput for each ultrasound practitioner and put in place a locally agreed action plan to enable them to meet the minimum throughput
- send and provide feedback on DQASS detailed ultrasound reports for each individual ultrasound practitioner
- implement and monitor any supportive red flag action plans
- review the SSS resource every 2 years; all new SSS and deputy SSS should review the SSS resource when they start in the role
The SSS should also have a local documented process for the above actions.
DQASS identity codes
Ultrasound practitioners must have a unique identity code matched to the ultrasound department(s) where they work to participate in DQASS.
Trainee ultrasound practitioners
A trainee will need a unique DQASS identity code once they are able to achieve nuchal translucency (NT) and crown rump length (CRL) measurements with minimal guidance from the supervising practitioner.
A DQASS identity code is different from a FMF identity code.
The SSS should email DQASS at dqass@plymouth.ac.uk with the practitioners name and their associated hospital/unit(s) to obtain a DQASS identity code for the trainee.
DQASS will issue an identity code with the suffix T to indicate a practitioner in training (for example, 123456T).
The training process should take no longer than 6 months. The training code T will remain valid for this time. If training is not completed within 6 months, the SSS should document reasons and contact DQASS.
The trainees should follow the 2-part training process as outlined in education and training for ultrasound practitioners in the FASP handbook.