Abstract:

Objective Through organizing a proficiency evaluation activity for animal illuminance testing laboratories, to assess the accuracy of testing data from participating laboratories, and to propose suggestions for testing methods. Methods In September 2024, China National Institute for Food and Drug Control (NIFDC) organised reference laboratories to conduct on-site testing through open registration. A total of 35 laboratories participated, completed on-site testing, and submitted their reports. The samples to be tested were two adjacent guinea pig breeding rooms in the NIFDC laboratory animal facility. In order to reduce the impact of room voltage fluctuations on animal illumination, chip on board (COB) light sources powered by regulated power supply were used, and brightness was adjusted by regulating voltage output. Split-level test sample pairs were used to set animal illuminance in both rooms, and the reference laboratories conducted testing according to Laboratory animals——Environment and housing facilities (GB 14925-2023). Each reference laboratory was assigned a 3-digit random code, conducted 2 tests for each breeding room, and submitted an on-site test report, original records, and illuminance meter verification or calibration certificate. WPS Spreadsheet 12.1 was used to summarize data, Grubbs' test (α=0.01) was used to check the data and remove outliers, and SPSS 26.0 software was used for data processing and graph drawing. The median value from each reference laboratory was used as the specified value, the robust standard deviation was used as the uncertainty, the robust z-score method (both intra-laboratory and inter-laboratory z-scores) was used to evaluate the test results from each laboratory, and the factors affecting results were analyzed from aspects of personnel, equipment, and operational environment. Results Under the detection level of α=0.01, no outliers were identified. The specified values for Room 1 and Room 2 were 17.80 lx and 19.00 lx, respectively. The results obtained from 34 laboratories were evaluated as "satisfactory", while the results from one laboratory were "unsatisfactory". Through analysis of illuminance meter calibration certificates from various laboratories, it was found that some reference laboratories had insufficient calibration points and coverage, which caused test results to fail to accurately reflect the actual illuminance of the facility. Conclusion The present study reveals that factors such as personnel, equipment, and operation environment have different impacts on animal illuminance measurements. The present study concentrates exclusively on animal illuminance in guinea pig breeding rooms, where the testing environment is relatively dim. Future research should focus on the development of more efficient methods for selecting measurement sites, with the combination of illuminance meters equipped with wireless probes and storage functions to enhance testing efficiency.

Key words: Laboratory animal, Animal illuminance, Proficiency testing, Illuminance meter, Individually ventilated cages