Evaluating the Implementation of the Rapid Prenatal Exome Sequencing Service in England.

Introduction: In October 2020, a national rapid prenatal exome sequencing (pES) service was rolled out across the English National Health Service (NHS). This service is delivered by multiple clinical and two laboratory teams. While there was high level national guidance to support implementation, it was unclear how the service had been delivered in practice. This study evaluated pES service implementation across England, using the major system change (MSC) framework to explore links between implementation approaches and outcomes.

Methods: We conducted a national mixed-methods multi-site study of 17 clinical genomics services, their linked fetal medicine services and two laboratories delivering the pES service. The MSC framework informed the study. Key documents, semi-structured interviews (eight national service developers, 55 staff), and surveys (n = 159 staff) were analysed using inductive and deductive thematic analysis and descriptive statistics. Findings were integrated.

Results: Implementation was influenced by a range of factors including evidence of benefit, laboratory service reconfiguration, and stakeholder support. Local implementation approaches varied; seven models of service delivery were identified. Key differences between models included leadership, staffing, and multidisciplinary team approaches. Local staff factors (e.g., time, capacity, attitudes), pES service factors (e.g., communication/collaboration, logistics), and organisational factors (e.g., infrastructure and previous experience) influenced implementation.

Conclusion: We have identified multiple barriers and facilitators that are associated with implementing a major change to genomic services in a complex national healthcare system. This study highlights which models of pES may work in practice and why. Findings will inform future development of the pES service.