Unlike sampling, GMP (Good Manufacturing Practice as defined by 501(B) of the 1938 Food, Drug, and Cosmetic Act (21USC351) looks at the integrity of the manufacturing process itself that is used for medical device manufacture.

An extremely important part of GMP is documentation of every aspect of the process, activities, and operations involved with medical device manufacture. If the documentation showing how the product was made and tested (which enables traceability and, in the event of future problems, recall from the market) is not correct and in order, then the product does not meet the required specification and is considered contaminated (adulterated in the US).

Additionally, GMP requires that all manufacturing and testing equipment has been qualified as suitable for use, and that all operational methodologies and procedures demonstrate that they can perform their purported function. This bears on the integrity and FMP of a wide range of medical products and devices, such as leak testing blood collection kits and implanted medical devices such as pace makers, or flow testing obturators and other laparoscopic instruments, crack pressure testing of medical check valves, calibration of on-demand oxygen delivery systems, or functional testing such as the sufflation and insufflation capabilities of laparoscopic instruments.