Pharmacy Cleanroom Certification: USP 797 Requirements

It is the testing that demonstrates a sterile compounding suite still performs to its design classification. Under USP General Chapter <797> the primary and secondary engineering controls must be certified before compounding begins and recertified at least every six months. Testing normally follows the CETA Certification Guide for Sterile Compounding Facilities, CAG-003, which is the reference most certifiers in this space work to.

At least every six months. It is also event-triggered: recertification is required after any redesign or construction work, after a primary engineering control is relocated, after a HEPA filter is replaced, and after a structural modification to the room. Sites that only diarise the six-month interval routinely get caught out by the event triggers.

Yes, and this is the point most facilities miss until it costs them. Any construction or redesign affecting the engineering controls restarts the clock regardless of where you sit in the six-month cycle. A filter change, a hood relocation or a wall alteration all require recertification before compounding resumes, which means the construction schedule and the certification schedule have to be planned as one thing rather than two.

USP <797> requires the engineering controls to be “independently certified” but does not define independence in the chapter itself. In practice the requirement is given teeth downstream, by the owner specification, by your own quality unit, and by accreditation bodies. The common route is a certifier working to CETA CAG-003. Note the credential boundary: NEBB Cleanroom Performance Testing covers ISO 14644 testing and is not the sterile compounding credential.

For general ISO 14644 testing there is no regulatory prohibition — NEBB certifies contractor firms and its governing procedures contain no conflict-of-interest clause. For USP <797> sterile compounding we take the conservative position: we build, remediate and support, and the classification certificate is issued by an independent CETA-qualified certifier. That keeps the evidence clean for an inspector and removes an argument you do not want to have during a survey.

Airborne particle counts to establish ISO classification, HEPA filter integrity testing by leak scan, airflow velocity and volume measurement, room pressure differential verification, airflow visualization or smoke study to demonstrate unidirectional flow and sweep, and temperature and humidity verification. The specific battery and acceptance criteria follow CAG-003 and the facility design.

The primary engineering control — the hood or isolator where the critical site is exposed — must maintain ISO Class 5 conditions. The buffer room housing it is typically ISO Class 7 and the ante-room ISO Class 8, though the ante-room classification depends on whether the suite handles hazardous drugs. Classification is established under defined occupancy conditions, not on an empty room.

USP <800> covers hazardous drug handling and inverts part of the pressure logic. A containment suite runs negative to the adjacent space to keep hazardous airborne material in, where a conventional sterile suite runs positive to keep contamination out. That usually requires dedicated external exhaust, a containment primary engineering control, and a room pressure regime that has to be proven at certification.

Most failures trace back to the build rather than to housekeeping. Pressure cascade that cannot hold across the ante-room and buffer room, insufficient air changes for the classification, HEPA leaks at the filter frame or gasket rather than in the media, envelope leakage through penetrations for process services and electrical, and airflow patterns disturbed by equipment placed after the room was designed.

Remediation, then recertification. Diagnosis comes first, because pressure and particle-count failures usually have a physical cause that testing alone will not identify: envelope leakage, a penetration that was never sealed properly, undersized supply, or an unsealed service crossing. We fix the cause, then an independent certifier retests.

The testing itself is typically a matter of hours to a day for a small suite, but the schedule that matters is the remediation-and-retest loop if something fails. Facilities that treat certification as a single scheduled morning rather than as a possible cycle are the ones that end up with compounding suspended while a fix is sourced.

Cost depends on the number of rooms and primary engineering controls, the test battery required, and whether hazardous drug containment is involved. The more useful figure to plan around is the cost of failure: a suite that cannot compound is losing revenue every day it is down, which usually dwarfs the certification fee.

We build, remediate and support. We design and construct the suite, correct what fails, and coordinate with the certifier so the retest happens as soon as the fix is verified. The certificate itself comes from an independent CETA-qualified certifier. We do not issue the <797> classification certificate for rooms we built.

The device providing ISO Class 5 air at the critical site: a laminar airflow workbench, a biological safety cabinet, a compounding aseptic isolator or a compounding aseptic containment isolator. It sits inside the buffer room, which is the secondary engineering control. Relocating a PEC triggers recertification.

Certification demonstrates the room and its engineering controls meet their physical performance specification. Validation, in the wider sense, covers whether the processes carried out in that room reliably produce what they are meant to — including media fills, personnel competency and cleaning validation. Certification is one input to a compliant operation, not the whole of it.

Continuous differential pressure monitoring between the ante-room, buffer room and adjacent space is standard practice and pressure readings are reviewed as part of routine operation. Certification verifies the design cascade is achieved; continuous monitoring is what tells you it is still being achieved on a Tuesday afternoon in August.

A certificate naming the standard, the classification achieved, the occupancy state tested and the sample locations; particle count data by location; HEPA filter leak scan results identified to filter serial number and position; airflow velocity and volume readings; pressure differential records against the design cascade; and airflow visualization evidence where performed.

Yes, and most of this work is exactly that rather than new construction. The constraints are ceiling height for the air handling, a route for dedicated exhaust if USP <800> applies, structural capacity, and finding a way to keep the rest of the pharmacy operating while the suite is built. The exhaust route is usually the hardest of the four.

USP <800> for hazardous drugs, USP <795> for non-sterile compounding, ISO 14644-1 and -2 for classification and monitoring, and CETA CAG-003 as the certification guide. State boards of pharmacy add their own requirements, and those sometimes exceed the USP baseline, so the governing specification is whichever is stricter.

The room or rooms and their intended classification, whether hazardous drugs are handled, the primary engineering controls in use or planned, the existing air handling and whether dedicated exhaust is available, the building constraints, and whether this is a new build, an expansion or remediation after a failed certification.