Once or twice a year, a certifier hands you a PDF. It runs twenty to forty pages, most of it tables. You confirm it says the room passed, you file it, and you move on.
Then an inspector asks why the particle count sample locations changed from last year, or why the report is dated six weeks after the test, and the document you filed without reading becomes the document you have to defend.
Here is what is actually in that report, section by section, and what to check in each one.
Start With the Cover Page
Four things, before you read a single test result.
The test date and the issue date. These are different dates and both matter. Your compliance interval runs from the test, not from when the paperwork arrived. A report issued six weeks after testing has left you with six weeks of documentation you could not have produced on request.
The scope. Every classified room and every primary engineering control should be listed by name and identifier. Compare that list against your own inventory — not against last year’s report, which may carry the same omission. A cabinet that moved to a different room, a hood added during a renovation, or a room renamed after a remodel is the single most common way a facility ends up with an uncertified device it believed was covered.
Who performed the work. The individual certifier should be named, with accreditation identified. For Class II biological safety cabinets, that means NSF/ANSI 49 accreditation held by the person who actually performed the testing — not a company-level claim, and not accreditation belonging to someone who was not on site.
As-found versus as-left. If anything was adjusted during the visit, the report should show both states. A report showing only final passing values is telling you what the room became, not what it was when your staff were compounding in it the day before.
The Instrument List
This is the section nobody reads and the section that decides whether the rest of the report means anything.
Every instrument used should appear with make, model, serial number, calibration date, and calibration due date. Then do the arithmetic yourself once: was every instrument in current calibration on the date of the test? Certificates that expired between the test and the report issue are fine. Certificates that expired before the test invalidate the data collected with them.
If instruments are listed without serial numbers, the report cannot be reconstructed or defended. There is no way for anyone — you, your certifier, or an inspector — to establish later which device produced which number.
The Tests
Airborne particle count and ISO classification
Performed to ISO 14644-1. Three things should be visible in this section.
State of occupancy. The report must state whether the room was tested as-built, at-rest, or operational. These produce materially different results, and a room certified at-rest is not evidence of anything about the room during compounding. Your certification should reflect the state your facility actually requires.
Sample locations. ISO 14644-1 determines the minimum number of sample locations from the room area, and the locations should be distributed across the room rather than clustered where results are convenient. The location count should be justified, and it should not change year to year without explanation — because that is precisely the question an inspector will ask.
The classification being applied. The report should state which ISO class the room is held to and show the measured concentrations against that limit, not simply against “pass.”
Air change rate
The report should show its work: measured supply air volume, room volume, and the resulting air changes per hour. ACPH is a calculation, and a result presented without the inputs cannot be verified by anyone.
Under USP <797>, an ISO 7 buffer room used for sterile compounding requires a minimum of 30 ACPH. Note carefully that the 12 ACPH figure appearing in USP <800> applies to hazardous drug storage areas, nonsterile HD compounding C-SECs, and C-SCAs — not to ISO 7 buffer rooms used for sterile HD compounding, which require 30 ACPH. This is the single most frequently transposed number in facility documentation, and it appears in vendor reports as often as in facility SOPs.
Room pressure differentials
USP <797> requires a minimum differential of 0.020-inch water column between each ISO classified area — for example, between the buffer room and the ante-room — and not less than 0.020-inch water column between the ante-room and the adjacent unclassified area. Hazardous drug compounding rooms under USP <800> run the other direction, at a negative differential of 0.010 to 0.030-inch water column relative to adjacent spaces.
The report should identify each room pair, the direction of the differential, and the measured value. Then do something most facilities skip: compare those readings against what your continuous monitoring system was displaying the same day. A meaningful disagreement between your certifier’s calibrated instrument and your wall-mounted monitor means one of them is wrong, and you would rather learn which during a certification visit than during an inspection.
HEPA filter installation leak testing
This is a scan, and the distinction matters. A downstream particle count taken near a filter is not a leak test. A proper installation leak test challenges the filter with a known upstream aerosol concentration and scans the filter face, frame, and gasket seal at a controlled rate.
The report should state the upstream challenge concentration, the scan methodology, the acceptance limit applied, and — where leaks were found — their location, size, and the repair performed, with the repair area assessed against the allowable limit. A line reading “HEPA integrity: pass,” with no challenge concentration and no scan documentation, is not a leak test result. It is an assertion.
Primary engineering control performance
For Class II biological safety cabinets tested to NSF/ANSI 49, expect downflow velocity readings across the work surface with the average and uniformity reported, inflow velocity with the calculation method identified, and the filter leak test results. Laminar airflow workbenches and compounding aseptic isolators carry their own test sets; in every case the acceptance criteria should be printed next to the measured values rather than left implicit.
Airflow visualization
CETA CAG-003 addresses dynamic airflow smoke pattern testing, and this is the test most likely to be quietly skipped, because it takes time and produces no number. It should be documented, and where video was recorded, the report should reference it and the video should be retrievable. Smoke studies are also the test most likely to reveal a real problem that every numerical test passed — a return grille placed where it pulls air across a work surface will not show up in a velocity average.
Temperature and relative humidity
Recorded at the time of testing, against the limits applicable to your operation — under USP <797>, temperature of 20°C or cooler and relative humidity below 60%. These are point-in-time readings and do not substitute for your continuous monitoring records, but a certification-day reading that sits far from what your logs show is worth explaining before someone else asks.
The Deviations Section
This is where an experienced inspector goes first, and often where facility staff have never looked.
Every out-of-specification result should appear with the measured value, the applicable limit, the probable cause, the corrective action taken, and the retest result. “Pass after adjustment” without as-found data tells you nothing about the condition your facility was operating in.
And if a room failed, the report should say so in language that cannot be misread. A certification report that reads as passing while burying a failure in a table is a liability, not a favor.
Nine Red Flags
- Instruments listed without serial numbers or calibration dates
- Pass/fail conclusions with no measured values behind them
- Acceptance criteria never stated, only implied
- Particle counts with no state of occupancy and no sample location rationale
- HEPA “integrity testing” with no upstream challenge concentration or scan documentation
- Room names, device identifiers, or dimensions that do not match your facility
- An issue date sitting weeks or months after the test date
- Adjustments performed with no as-found data recorded
- Informative annexes cited as though they were mandatory requirements — ISO 14644-3 Annexes A, B, and C carry the weight of guidance; your mandatory requirements flow from USP <797>, USP <800>, and CETA CAG-003
What to Do With It
Read the scope against your own equipment inventory. Confirm the interval against your requirement. File it alongside your environmental monitoring data rather than separately, since an inspector will read them together. And bring the deviations section into your inspection preparation instead of discovering it during the inspection.
Then ask your certifier to walk you through the report. Any certifier should be able to explain every number in a document bearing their name, and one who cannot is telling you something worth knowing.
Want a second opinion on a report you already have? Send it to LabCertTech and we will read it with you — no obligation to switch vendors.