Every product or device is prequalified on the basis of a performance specification. This describes the specific environment in which the product will operate and defines the functional requirements that it must fulfil in order to operate successfully in that environment. A performance specification thereby establishes standards of adequate performance.
Additionally, each performance specification is accompanied by one or more verification protocols which specify the testing procedures that must be used to demonstrate product compliance with the functional requirements and in order to attain prequalification.
Every prequalified product is reviewed once annually to ensure that it continues to meet current performance specifications.
WHO relies on user feedback about equipment performance under field conditions to revise and improve product standards and specifications.