The terms and defination
The term standard operating procedure, or SOP, is used in a variety of different contexts, including healthcare, aviation, education, industry, and military.
The U.S. military sometimes uses the term Standing — rather than Standard — Operating Procedure, because a military SOP refers to a unit’s unique procedures, which are not necessarily standard to another unit. “Standard” could imply that there is one (standard) procedure to be used across all units.
Further application is with triage, when limited resources get used according to an assessment on ranking, urgence and staffing possibilities.  Study director is mainly responsible for SOP. Quality Assurance Unit are individuals who are responsible for monitoring whether the study report and tests are meeting the SOP.
SOP’s can also provide employees with a reference to common business practices, activities, or tasks. New employees use an SOP to answer questions without having to interrupt supervisors to ask how an operation is performed. The international quality standard ISO 9001 essentially requires the determination of processes (documented as standard operating procedures) used in any manufacturing process that could affect the quality of the product.