You bring up a great point Talha. Depending on the product or service you are procuring a certain standard must be met by the vendor. For a critical component, one that will be part of the implanted device, the supplier must meet industry and OEM quality guidelines in order to be purchased. However, there may be a plethora of items that are low risk or are simply production stock items that may not need as rigorous of quality control and may be bought from on the shelf as miscelaneous parts.