Participation in proficiency tests is an essential requirement of ISO/IEC 17025 for testing and calibration laboratories. These tests aim to evaluate performance of laboratories for specific analytical methods, identify problems and assist in initiating corrective actions for improvement, find source of error in measurement result and validate uncertainty. The accredited Gamma-Ray Spectroscopy Laboratory at the Lebanese Atomic Energy Commission, participates yearly in proficiency test organized by the International Atomic Energy Agency (IAEA)-ALMERA Network-Analytical Laboratories for the Measurements of Environmental Radioactivity and the Department of Energy-USA, Mixed Analyte Performance Evaluation Program (MAPEP-DOE-USA). This paper showed how proficiency tests had helped the laboratory to improve adopted analytical protocol through the corrective actions implemented for unacceptable results, and to provide advanced experience to the laboratory staff through the lessons learned. The Results were evaluated based on accuracy and precision criteria. The relative bias, Z-score and precision score values since 2005 are presented and discussed. The laboratory showed high performance over years with acceptable values for different radionuclides in various matrices.

参加能力测试是ISO / IEC 17025对测试和校准实验室的一项基本要求。这些测试旨在评估实验室针对特定分析方法的性能，发现问题并协助采取纠正措施以进行改进，发现测量结果中的错误来源并验证不确定性。黎巴嫩原子能委员会经认可的伽马射线光谱实验室，每年参加由国际原子能机构（IAEA）-ALMERA网络-环境放射性测量分析实验室和美国能源部混合组织的能力验证分析人员绩效评估计划（MAPEP-DOE-USA）。本文展示了能力测试如何通过采取纠正措施以达到不可接受的结果来帮助实验室改进已采用的分析规程，并通过所汲取的经验教训为实验室工作人员提供先进的经验。根据准确度和精密度标准对结果进行了评估。相对偏差，介绍并讨论了自2005年以来的Z得分和精确度得分值。实验室多年来表现出很高的性能，在各种基质中对于不同的放射性核素都具有可接受的值。