During performance qualification, the correct interaction of the accessories already tested as individual components is tested in larger units (Units Operations) such as air systems, purified water systems, filling and packaging lines.

As in the OQ, acceptance criteria are formulated and performance tests are carried out. This should show that the respective equipment, with the corresponding process, meets the intended requirements. PQ requires that OQ has already been completed.

When compiling the PQ test protocols, particular attention must be paid to the representative samples/test quantities. It should be shown that the interaction of the entire unit works properly and that the upper and lower limits have been tested.

For some subject areas in qualification, there are clear regulations for PQ. For rooms, PQ is required during operation. For utilities (air, water), PQs that include the first production year are required. The classic "water tracks" for process equipment also fall in the PQ phase. Water tracks clearly show the interaction of all components and the upper and lower control areas and partial load behaviour can be simulated cost-effectively.

Control tests that are used to define operational parameters can also be processed in PQ. This includes, e.g. qualification batches/engineer studies, that are required to establish the process management.

PQ can be omitted if the essential aspects, such as performance, interaction of the components and worst case conditions are dealt with in the process validation (PV).