Optimizing people's movement across the health system: a scoping review of referral systems within a primary health care approach.

Functional referral systems are critical to primary health care and universal health coverage. Referral and counter-referral are key relational mechanisms to link communities to the care they need and primary care to secondary and multi-sectoral services. Many referral systems are fragmented, leading to inefficiencies, coverage gaps, and compromised continuity and quality of care. In June 2024, we conducted a scoping review of PubMed, Global Index Medicus and WHO publication databases to identify referral coordination and process initiatives at national, subnational, and local levels.We classified reports from 181 papers into non-exclusive categories based on referral system design, operational elements, service delivery platform, and/or user group. Initiatives targeting referral system design included modelling, organization and assessment methodologies. Initiatives focusing on operational elements included networks and linkages, pathways and algorithms, e-referral systems and platforms, digital processes and tools, and facility-level processes and tools.When classified by service delivery platform, community-level initiatives emphasized improved recognition, screening, diagnosis, and communication by community health workers and use of SMS text messaging or mHealth apps. At initiating facilities, reports focused on standardizing referral criteria and protocols and optimizing communication with referral facilities, including for real-time clinical decision-making to improve timely referral and to reduce under- and over-referral. Structured algorithms and pathways were key to minimize the time between referral, diagnosis, and treatment for time-sensitive conditions. At receiving facilities, actions included supporting initiating facility clinical decision-making prior to referral, prioritizing urgent cases, and consistent counter-referral and/or onward referral.Findings are informing WHO guidance on two-way referral systems.