What guidelines should a laboratory use to set their own "control" and "action" limits?

The role of an external QAP service such as EQASRM is to provide an objective service by supplying a set group of samples and subsequently comparing results on a large scale. It is currently not our role to police or make decisions on the performance of your lab. How labs choose to interpret how they have performed in an EQA scheme should be decided by senior staff members and clearly set out in appropriate procedure manuals. We recommend labs refer to the WHO Manual for the Examination and Processing of Human Semen, 5th Edition, 2010, Cambridge University Press. Chapter 7, Quality Assurance and Quality Control, details methods of calculating control limits depending on variables specific to your lab.