Background
The increasing use of mobile messaging within healthcare, poses challenges for screening programmes, which involve communicating with large, diverse populations. This modified Delphi study aimed to create guidance regarding the use of mobile messaging for screening programmes, to facilitate greater, and equitable screening uptake.

Methods
Initial recommendations were derived from a literature review, expert scoping questionnaire, public consultation, and discussion with relevant national organisations. Experts from the fields of public health, screening commissioning, industry and academia voted upon the importance and feasibility of these recommendations across two consensus rounds, using a 5-point Likert scale. Items reaching consensus, defined a priori at 70%, on importance and feasibility formed ‘core’ recommendations. Those reaching this threshold on importance only, were labelled ‘desirable’. All items were subsequently discussed at an expert meeting to confirm suitability.

Findings
Of the initial 101 items, 23 reached consensus regarding importance and feasibility. These ‘core’ items were divided across six domains: message content, timing, delivery, evaluation, security, and research considerations. ‘Core’ items such as explicitly specifying the sender and the role of patient involvement in development of screening message research had the highest agreement. A further 17 ‘desirable’ items reached consensus regarding importance, but not feasibility, including the integration into GP services to enable telephone verification.

Interpretation
These findings forming national guidance for services, will enable programmes to overcome implementation challenges and facilitate uptake of screening invitations. By providing a list of desirable items, this study provides areas for future consideration, as technological innovation in messaging continues to grow.

Funding
NIHR Imperial Patient Safety Translational Research Centre.