Competency Assessment of Laboratories for Pesticide Residue Analysis in Cannabis, Hemp, and Derived Products Through Proficiency Testing Programs During 2020−2025

The PT use for Assess Laboratories Analyzing Pesticide in Cannabis, Hemp, and Related Products

Abstract

         Pesticide residues determinations in cannabis have become a major interest in Thailand due to the recent legalization and decriminalization of cannabis for medicinal uses since February 2019. To assure the reliability of the analytical results, the laboratories need to participate an interlaboratory comparison programme for external quality control. The Bureau of Quality and Safety of Food (BQSF) has organized a proficiency testing (PT) programme for analysis of multiple pesticide residues in cannabis, hemp and products, and continuously developed for six consecutive years since 2020 to 2025. The aim of the PT programmes is to gain information regarding the quality, accuracy, and comparability of the testing results reported by government and private laboratories in Thailand, thus to help evaluation and improvement of their performances. This study focused on the development of PT sample preparation including cannabis, hemp and product sample, as well as their homogeineity and stability testings. Moreover, the article summarizes the six years’ experience in processing and analyzing results for BQSF PT for pesticide residues in cannabis, as herbal medicine ingredients and food products. It provides an overview on the performance and progressive development of more than twenties laboratories throughout the years. Results are highlighted in terms of the number of participants, target analyte, z-score, false positive and false negative test results, and analytical methods used by laboratories. Overall, the performance of participating laboratories in the BQSF PT has been increased over time. The results of several rounds of PT programmes demonstrated the improvement of the measurement capability of the laboratories, whereas more capability-building in traceability of PT item with uncertainty evaluation is required for further improvement.