Laboratory Proficiency Testing and External Quality Assurance Participation Among Medical Laboratories in Akwa Ibom State, South South Nigeria

External quality assurance programmes and proficiency testing provide objective evidence of laboratory competence and are integral to sustaining diagnostic reliability across healthcare systems. This study assessed the level of participation in external quality assurance schemes and proficiency testing among medical laboratories in Akwa Ibom State, South South Nigeria. A cross-sectional survey was conducted among 80 medical laboratories including public teaching hospitals, private laboratories, and faith-based institution laboratories. Data were collected via structured questionnaires administered to laboratory heads and supplemented by documentation reviews. Participation in any recognised proficiency testing scheme was confirmed in only 41.3% of laboratories. Public tertiary hospital laboratories showed the highest participation at 85.7%, while private and primary health facility laboratories had the lowest at 22.4%. Major barriers to participation included cost of programme subscription, lack of awareness among laboratory managers, and absence of institutional policy mandating participation. Laboratories enrolled in the Nigeria External Quality Assurance Scheme reported significantly fewer analytical error complaints from clinicians. Haematology and clinical chemistry were the most tested disciplines. The study identifies major gaps in external quality assurance engagement among South South Nigerian laboratories and recommends mandatory EQA participation as a condition for laboratory licensing renewal, subsidised government enrolment for public health facility laboratories, and establishment of a zonal mentorship network for laboratories seeking accreditation. Keywords: external quality assurance, proficiency testing, laboratory accreditation, NEQAS, Akwa Ibom State