Professional Application of Enzyme-Linked Immunosorbent Assay in Infectious Disease Diagnosis at Secondary Health Facilities in Plateau State

Enzyme-linked immunosorbent assay technology is central to the serological diagnosis of infectious diseases including HIV, hepatitis B and C, typhoid, and malaria, and its professional application in secondary health facilities in Plateau State requires systematic evaluation for diagnostic quality and operational effectiveness. This study evaluates the professional application of ELISA in infectious disease diagnosis at eight secondary health facilities in Plateau State, covering facilities in Jos, Shendam, Pankshin, and Wase LGAs. A structured facility audit instrument covering ELISA equipment type, assay repertoire, kit procurement management, internal quality control performance, cold chain maintenance, result turnaround, and staff training records was applied at each facility. Concurrent external quality assurance performance was assessed by reviewing participation certificates and EQAS grading records. Parallel testing was conducted for HIV, HBsAg, and Typhoid ELISA results against a reference facility standard in a subset of twenty samples per facility. Results show that all eight facilities operated automated or semi-automated ELISA platforms, but only three maintained calibrated and serviced equipment with current maintenance records. Cold chain lapses affecting kit storage were identified in five facilities. Internal quality control using kit-supplied controls was routinely documented at six facilities but with incomplete Levey-Jennings chart maintenance. Parallel testing revealed clinically significant discordant results for typhoid ELISA in three facilities, raising concerns about test validation in these settings. The study recommends a Plateau State ELISA quality management improvement programme. Keywords: ELISA, infectious disease diagnosis, quality management, secondary health facilities, Plateau State.