Performances and determinants of proficiency testing in clinical laboratory services at comprehensive specialized hospitals, northwest Ethiopia.

Proficiency testing (PT) is an impartial laboratory performance-evaluating system using an independent body. It is a mandatory accreditation requirement and means for improving the laboratory's performance. The study aimed to evaluate the performance of PT, with a focus on identifying and discussing determinants that influence PT performance at comprehensive specialized hospitals in northwest Ethiopia. A retrospective cross-sectional study was carried out from 2020 to 2022. Using a convenient sampling technique, laboratory tests with recorded PT results in each hospital laboratory were included. A data collection template and customized checklists were used to collect the data. Epi Data Version 3.1 for data entry and STATA Version 14.1 for cleaning and analysis were used. Binary logistic regression analyses were used. Variables with p < 0.05 in the multivariable logistic regression were considered to be statistically significant. Over nine cycles, 3807 PT challenges were distributed. The total failure rate of the laboratories was 32.4%, with a peak failure rate of 40.3% in 2020, after which the failure rate was decline to 20.6% in 2022. Among the five laboratory sections, molecular biology had the lowest failure rate (22.2%), while microbiology had the highest failure rate (56.5%). Multivariate logistic regression revealed that PT results reported without appropriate unit of measurement (AOR 7.5), lack of corrective action for PT nonconformance (AOR 7.1), and reagent unavailability (AOR 6.1) had significant effects on PT performance (p < 0.001). The results of this study showed that the overall performance of the laboratory was lower. Reporting PT results without appropriate units of measurement and not taking corrective action for PT nonconformance were the major aggravating factors for high failure rates.