IQ, OQ and PQ: what equipment qualification actually involves

If you buy an instrument for a regulated lab, the purchase order is not the end of the job. Before that instrument can produce data anyone will accept, you have to show it was installed properly, that it works the way the manufacturer says, and that it does what your method needs. That is what IQ, OQ and PQ are for.

The three letters get used loosely, so here is what each stage actually covers.

IQ: installation qualification

IQ documents that the equipment arrived as ordered and was installed under the right conditions. It is the least glamorous stage and the one people most often rush.

A proper IQ records the model and serial number, the firmware version, what was in the box against what was on the order, and the utilities the unit is connected to: voltage, water quality, drainage, extraction, bench loading. It also captures the environment. An analytical balance on a bench that shares a wall with a centrifuge will haunt you six months later, and the IQ is where that gets noticed.

OQ: operational qualification

OQ shows the instrument performs to specification across its working range, empty and under controlled conditions. Think of it as testing the machine, not your method.

For an oven or an incubator that means temperature mapping at the setpoints you will actually use, with calibrated sensors placed through the chamber rather than one probe in the middle. For a pipette it means gravimetric testing at nominal, mid and low volume. For an autoclave it means checking that the cycle reaches and holds the stated temperature and pressure, with the drain probe and the load probes agreeing.

OQ is also where you find out whether the acceptance criteria you wrote are realistic. A tolerance copied from a brochure is not the same as one your unit can hold in your room.

PQ: performance qualification

PQ is the stage people skip, and it is the one auditors care about most. It demonstrates that the instrument does the job in your hands, with your load, your samples and your operators.

A sterilizer that passes OQ empty can still fail with a full basket of wrapped instruments, because steam has to reach every surface. An incubator qualified empty behaves differently once it is packed with plates. PQ runs the real configuration, at the worst case, and repeats it enough times to show the result was not luck.

How often does it need repeating?

IQ happens once, unless the instrument moves. OQ and PQ get repeated on a schedule, after any major service or relocation, and after a change that could affect performance: a new firmware version, a different load pattern, a moved chamber shelf.

Annual is common for OQ. PQ frequency depends on how critical the process is and what your quality system says. If you are working to GMP, the schedule belongs in your validation master plan rather than in someone's calendar.

Where the paperwork usually falls apart

Three things account for most of the findings we see.

• Calibration certificates with no traceability. A certificate is only worth something if the reference standard behind it is traceable and still in date.
• Acceptance criteria written after the test. Criteria decided once the numbers are in are not criteria.
• No record of who did it. Signatures, dates and the instrument's own log need to agree.

Getting it done

Qualification is easiest when it is planned with the purchase rather than bolted on afterwards. We handle IQ, OQ and PQ for the equipment we supply, and for equipment already in the lab, including temperature mapping and pipette calibration. The documentation comes in a form you can hand to an auditor.

If you are specifying a new instrument, tell us the standard you work to and we will price the qualification alongside the equipment so there are no surprises later. You can see the full range on our services page, or send us the details and we will come back with a written quote.