ISO 23611-1:2006 specifies a method for sampling and handling earthworms from field soils as a prerequisite for using these animals as bioindicators (e.g. to assess the quality of a soil as a habitat for organisms).
ISO 23611-1:2006 applies to all terrestrial biotopes in which earthworms occur. It is not applicable for semi-terrestrial soils and it can be difficult to use under extreme climatic or geographical conditions (e.g. in high mountains).