protocol for interlaboratory comparison 

https://doi.org/10.1351/goldbook.08105
Detailed set of instructions describing the objectives, design, conduct, and reporting of an interlaboratory comparison.
Source:
PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1034 (https://doi.org/10.1515/pac-2019-0819)