A manufacturer I worked with early in my career had been sending samples to the same lab for three years before anyone noticed the lab’s accreditation scope didn’t cover the specific method they were using. The Certificates of Analysis looked fine. The reports came back on time. But the accreditation they were relying on for regulatory purposes was, in practice, meaningless for that test. Three years of data, and a significant portion of it couldn’t be used to defend a product claim.
That kind of gap is more common than most quality managers realize. Qualifying a testing laboratory isn’t just about checking a box — it’s about understanding exactly what a lab is and isn’t certified to do, and whether their operational reality matches what’s on paper.
ISO/IEC 17025:2017 accreditation is the baseline. Any laboratory you use for regulatory or quality purposes should hold current accreditation from a recognized accreditation body. In the United States, that typically means A2LA (American Association for Laboratory Accreditation), NVLAP (National Voluntary Laboratory Accreditation Program), or Perry Johnson Laboratory Accreditation (PJLA). Each of these bodies is a signatory to the ILAC Mutual Recognition Arrangement, which means their accreditations are recognized internationally.
But accreditation status alone isn’t enough. You need to verify the scope. Every accredited lab has a published scope document that lists the specific tests, methods, and matrices covered by the accreditation. A lab can be ISO 17025-accredited and still be running a specific test outside their accredited scope — which means that test carries no accreditation backing. Always download and review the current scope document directly from the accreditation body’s website, not from the lab’s own materials.
For FDA-regulated products — dietary supplements under 21 CFR Part 111, food under 21 CFR Part 117, or cosmetics under the Modernization of Cosmetics Regulation Act (MoCRA) — you’ll also want to confirm the lab has experience with FDA-regulated matrices and understands the documentation requirements those regulations impose.
There’s a difference between a lab that has a method and a lab that has validated that method for your specific matrix. Method validation — confirming that a test performs reliably in your product type — matters enormously when you’re dealing with complex matrices like botanical supplements, food products with high fat content, or cosmetics with preservative systems that can interfere with microbial testing.
Ask the lab directly: “Has this method been validated for my matrix?” If the answer is vague or they pivot to talking about their equipment, that’s a signal to probe further. A well-run lab will have validation data they can share, at least in summary form. They should be able to tell you the method’s limit of detection, limit of quantitation, and any known matrix interferences.
For methods referenced in FDA guidance — USP <61> and <62> for microbial testing, USP <232> and <233> for elemental impurities, AOAC methods for nutritional analysis — confirm the lab is running the current version of the method and has the equipment and reagents to do it properly.
Standard turnaround times vary by test type. Microbial testing typically requires 5–10 business days for full USP <61>/<62> panels. Heavy metals by ICP-MS can often be turned around in 3–5 business days. Nutritional panels by AOAC methods tend to run 7–14 business days depending on the analytes.
Rush turnaround is available at most labs, but it comes at a cost — typically 50–100% premium — and it strains lab capacity. If your production schedule requires consistent 3-day turnaround on complex panels, be direct with the lab about that requirement before you commit. Some labs can accommodate it; many can’t without compromising queue management.
Ask about their capacity during peak periods. If a lab serves a large number of supplement manufacturers, their December and January turnaround times may be significantly longer than their standard quotes suggest.
A formal lab qualification audit doesn’t have to be an on-site visit, though on-site is preferable for primary testing partners. At minimum, request a completed supplier questionnaire covering:
Sub-contracting is a common source of quality gaps. A lab may be accredited for a test but routinely sub-contract it to a facility with different quality standards. Your qualification should cover the full testing chain.
A few things I’ve seen that should give any quality manager pause:
A lab that can’t provide a current, downloadable accreditation scope document. A lab that quotes turnaround times without asking about your matrix or test volume. A lab that doesn’t ask about your regulatory requirements before proposing a testing panel. A Certificate of Analysis template that doesn’t include method references, accreditation numbers, or uncertainty statements.
None of these are automatic disqualifiers, but each one warrants a direct conversation. The labs that make the best long-term partners are the ones that ask as many questions as you do.
Before approving a new testing laboratory, confirm you can answer yes to each of these:
At Aurora TIC, we help manufacturers build lab qualification programs that hold up under FDA scrutiny and scale as product lines grow. The checklist above is a starting point — the specifics will vary by product category, regulatory context, and testing volume. Requirements vary by product category; consult a qualified regulatory expert for your specific situation.