Laboratory Service Readiness and Diagnostic Availability in Rural Primary Healthcare A Systematic Review of Assessment Frameworks and Regional Disparities

Background: Access to functional diagnostic laboratory services constitutes a foundational pillar of primary healthcare delivery. This systematic review examines global and national standards for laboratory service readiness, with a focused analysis of the World Health Organization (WHO) Service Availability and Readiness Assessment (SARA) framework. Objectives: To synthesise evidence on laboratory service readiness frameworks, characterise public-private disparities in diagnostic capacity, and identify structural determinants of laboratory dysfunction in geographically challenged mountainous regions with particular reference to Arunachal Pradesh, India. Methods: A systematic search was conducted across PubMed, EMBASE, WHO IRIS, Cochrane Library, and grey literature repositories covering the period 2000–2024. Studies were included if they reported quantitative or mixed-method assessments of laboratory readiness, diagnostic availability, or health facility surveys in primary care settings. Quality appraisal used the Mixed Methods Appraisal Tool (MMAT). Results: Sixty-three studies met inclusion criteria. Laboratory readiness scores below WHO benchmarks were consistently observed across low- and middle-income countries (LMICs), with sub-national variation accentuated in mountainous and remote settings. The SARA framework emerged as the most widely validated tool, though its application in geographically fragmented regions reveals critical blind spots around cold-chain logistics, supply-chain resilience, and human-resource retention. Public sector facilities demonstrated significantly lower readiness indices than private counterparts on equipment functionality, reagent availability, and quality assurance participation. Conclusions: Laboratory service readiness in rural primary healthcare remains critically deficient, with the highest deficits concentrated in mountainous regions such as Arunachal Pradesh. Adaptation of the SARA framework to account for terrain, seasonal accessibility, and State-specific epidemiological burdens is essential. Multi-stakeholder investments in solar-powered infrastructure, mobile diagnostics, digital health integration, and targeted human-resource strategies are urgently required.