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What are the changes to DQASS and what do they mean for sonographers?

11 December, 2017

Author: Nadia Permalloo, Head of Quality Assurance Development (clinical), Public Health England Screening

Fetal scan

DQASS (Quality Assurance Support Service) was set up in 2006 by the NHS Fetal Anomaly Screening Programme to monitor and support the quality and effectiveness of the national screening programme for Down’s, Edwards’ and Patau’s syndromes in England.

DQASS provides six-monthly feedback and ongoing support to screening laboratories and ultrasound practitioners involved in the NHS screening programme.

Flags are assigned to a dataset of nuchal translucency (NT) and crown rump length (CRL). These flags indicate the bias of the dataset which is the extent of the measurement deviation from the Fetal Medicine Foundation reference curve. A red flag is currently assigned to data sets (not individuals) where the bias is greater than 0.4mm.

The flag system is designed to help the screening support sonographer (SSS) identify where to focus training efforts and there is a management protocol outlined in the ultrasound practitioner’s handbook which takes account of other factors that may affect the bias.

What is being changed and why?
DQASS changed the threshold of red flags from 0.4mm to 0.3mm from October 2017 (DQASS cycle 23).

Over the last 10 years, DQASS has seen significant improvement in the screening programme as a whole but the number of red flags has remained consistent over the last two years. This change is being introduced to drive continuous improvement and consistency in the measurement of NTs and CRLs.

Public Health England screening has informed all SSSs, local screening coordinators and heads of midwifery about this change and will update the NHS FASP ultrasound handbook.

Please direct any queries about this change to the PHE screening helpdesk.

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