The four primary care (PC) core functions (the ‘4Cs’, ie, first contact, comprehensiveness, coordination and continuity) are essential for good quality primary healthcare and their achievement leads to lower costs, less inequality and better population health. However, their broad definitions have led to variations in their assessment, in the innovations implemented to improve these functions and ultimately in their performance.

To update and operationalise the 4Cs’ definitions by using a literature review and analysis of enhancement strategies, and to identify innovations that may lead to their enhancement.

Narrative, descriptive analysis of the 4Cs definitions, coming from PC international reports and organisations, to identify measurable features for each of these functions. Additionally, we performed an electronic search and analysis of enhancement strategies to improve these four Cs, to explore how the 4Cs inter-relate.

Specific operational elements for first contact include modality of contact, and conditions for which PC should be approached; for comprehensiveness, scope of services and spectrum of population needs; for coordination, links between PC and higher levels of care and social/community-based services, and workforce managing transitions and for continuity, type, level and context of continuity. Several innovations like enrolment, digital health technologies and new or enhanced PC provider’s roles, simultaneously influenced two or more of the 4Cs.

Providing clear, well-defined operational elements for these 4Cs to measure their achievement and improve the way they function, and identifying the complex network of interactions among them, should contribute to the field in a way that supports efforts at practice innovation to optimise the processes and outcomes in PC.