Choosing a Third-Party Laboratory: Six Things to Check

A third-party laboratory report looks authoritative, and it usually is. The trap is not forgery; it is scope. A laboratory can be genuinely accredited and still not be accredited for the test you sent it, on the material you sent, at the site that ran it. Accreditation is specific by design, and reading it as a general quality mark is the mistake that costs a batch.

There is a second trap underneath the first. When a test is outsourced, the responsibility for the result does not travel with the sample. The framework that governs contracted testing is explicit about that, and it is the reason the qualification work falls on the party placing the work rather than on the party performing it.

It is worth naming the document this is not. A producer's certificate of analysis is the maker's own report on the maker's own batch — useful and required, but not independent. A third-party report is different in kind: it is issued by a party with no stake in the batch passing, which is why the scope of that party's accreditation, and not the letterhead, is what you are really relying on. The rest of this note is about that second kind of document.

Three things that are not the same thing

The three documents a laboratory can show you have three different purposes, and a supplier of laboratory services will often present the strongest-sounding one for the work at hand.

What it is	What it covers	What it does not tell you
A quality management system certificate, such as ISO 9001	That the organisation runs a documented management system	Nothing about the technical competence of a specific test on a specific material
A test accreditation, such as ISO/IEC 17025	The competence, impartiality and consistent operation of the laboratory for the tests listed in its scope, at the sites listed	Nothing about material outside the scope, and nothing about whether the laboratory holds any authorisation to release a batch
A GMP authorisation or certificate	The activities a facility was inspected for	Nothing about whether the specific method you need has been validated at that site

None of the three replaces another, and holding one is not evidence of the others. That is worth saying plainly because the abbreviations look similar in a tender response and mean very different things in an inspection.

The scope of accreditation is the part to read

Accreditation documents are long and the interesting part is short. The scope lists the tests, the materials and the sites a laboratory is accredited for, and it is published — through the national accreditation body, and internationally through networks such as ILAC and, in Europe, the European co-operation for Accreditation. Before assigning work, check three things against it: the method, the material, and the location.

The location point is the one that gets missed. A laboratory group with several sites may hold an accreditation for one site and perform your test at another, especially when the work is routine. The scope names the site. If the site that will do the work is not named, the accreditation does not apply to your test, and the report will be no less accurate but considerably less useful.

The material point matters just as much for a specialist area like bile acids. A method validated on a tablet matrix is not automatically applicable to a raw material, and a laboratory accredited for one does not become accredited for the other by having the equipment. Ask for evidence that the method is suitable for the material you are sending, which is a different question from whether the laboratory owns the instrument.

Who is responsible when the test is outsourced

The European framework for contracted activities places the responsibility for assessment squarely on the party that places the work. That party has to satisfy itself about the legality, the suitability and the competence of the party that performs the work, and it has to do so before the work starts rather than after a result it does not like. Responsibility for the product decision does not transfer with the analysis.

The framework for active substances adds requirements around contracted parties in its own right, covering the quality agreement with the contract acceptor and the flow of information to the customer. In practice this means three things have to exist: a written agreement that sets out who does what, a documented assessment of competence for the specific work, and a route by which the customer can reach the original data if a result is questioned.

The last of those three is the one buyers test least and value most. If a result is disputed, the question becomes whether the raw data, the chromatograms, the integration and the audit trail can be produced. A laboratory that cannot offer that has given you a number rather than evidence.

What the report must show

• The method, and its version. A result without the method cannot be compared with anything, including the same test run elsewhere.
• The sample and how it was identified. What was received, with the supplier's batch identification carried through to the report.
• The site that performed the work. Named, not implied, because it is the site that holds the accreditation.
• The results beside the specification they are being compared against, so the reader does not have to supply the limits from memory.
• The dates of receipt and of testing, which matter for any claim about storage and for any holding-time question.
• The uncertainty where a result sits close to a limit, and the name of the person who authorised the report.

Two of those entries catch more problems than the rest. A result reported without the specification it was judged against invites the reader to assume a limit, and a result near a limit reported without uncertainty invites a decision that the number cannot support.

Why the report is not automatically the release document

A report from an accredited laboratory is evidence about a sample. Whether it can serve as the document that releases a batch is a different question, and it belongs to the quality unit rather than to the laboratory.

The distinction matters because the two documents are used for different things. A release document carries the authority of the system that released the batch, which means the laboratory producing it has to be operating within a framework the releasing party accepts, and the arrangement has to be covered by a written agreement between the two. A test report produced outside such an arrangement can be perfectly accurate and still not be usable in place of release testing.

There is a practical test for this. Ask which document the batch was released against, then ask whether the laboratory that produced the supporting results is named in the framework that governs the release. If the two answers do not connect, the report is evidence rather than a release document, and knowing which one you are holding prevents a file from being built on the wrong paper.

Questions to put to any laboratory

1. Is the method in your accreditation scope, for this material, at this site? The three qualifiers are the whole question.
2. How was the method transferred or verified for our material? A written procedure is not a demonstration of capability.
3. Who holds the raw data, and can we access it if a result is challenged? Ask before you disagree with a result, not after.
4. What is your position on out-of-specification results and deviations? The answer tells you whether the laboratory investigates or merely repeats.
5. Does a change in your method, or in your accreditation scope, trigger a notification to us? A silent change is the one that invalidates a comparison.
6. Which site will do the work, and is that the site on the report? These are sometimes not the same, and the report is what you keep.

None of these questions requires the laboratory to disclose anything confidential. All six are answerable from its own scope document and quality agreements.

Where this leaves you

A third-party report is evidence about a sample, and its weight depends on whether the laboratory was qualified for that specific work rather than in general. Read the scope before you read the result, put the requirement to demonstrate method suitability rather than to hold an instrument, and settle the question of raw-data access while the relationship is still friendly.

What we release against, and how external testing is qualified for it, is set out on our ursodeoxycholic acid page. If you want the testing position for a specific material discussed against your own acceptance criteria, you can raise it through a quotation request. For what a method has to be able to see before a result means anything, see what a stability-indicating method is, and for how a report's lines map onto your own specification, how to read a certificate of analysis.

This article describes laboratory qualification, accreditation and contracted-testing frameworks for quality, regulatory and procurement professionals. It states no therapeutic use, dose or indication for any substance, and no order quantity or lead time. Confirm all requirements against the current published guidance of the relevant authorities and accreditation bodies.

Frequently asked questions

What is the difference between ISO 9001, ISO 17025 and a GMP authorisation?

They are three different things with three different scopes. ISO 9001 certifies a quality management system. ISO 17025 accredits a laboratory for specific tests on specific materials at a specific site. A GMP authorisation or certificate reflects an inspection of a facility for the activities it lists. None of them automatically replaces another, and a certificate for one is not evidence of the others.

Does outsourcing a test transfer responsibility for the result?

No. Under the European GMP framework for contracted activities, the party that places the work remains responsible for assessing the competence and suitability of the party that performs it, and responsibility for the product decision does not transfer with the test. The contract acceptor takes on the work, not the ownership of the outcome.

What is the scope of accreditation and why does it matter?

It is the published list of tests, materials and sites for which a laboratory is accredited. Accreditation is specific by design, so a laboratory can be accredited for one method on one matrix and not for another. Before assigning work, check that the method and the material you need appear in the scope for the site that will actually perform the test.

What should a third-party test report contain?

Which method was used and its version, which sample was tested and how it was identified, which site performed the work, the results with the specification they are compared against, the date of receipt and of testing, and the person who authorised the report. Where a result is near a limit, an uncertainty statement is useful and its absence is worth noting.

How should method transfer to an external laboratory be handled?

As a documented exercise rather than a handover. The receiving laboratory needs to show that it can execute the method on your material, which usually means a written transfer or verification protocol, some comparative testing, and a record of the outcome. Receiving a written procedure does not demonstrate that the laboratory can run it.

Can a laboratory's own certificate of analysis be used as the release document?

That depends on whether the laboratory operates under a suitable authorisation for the work and whether the arrangement is covered by a written agreement. A report from an accredited laboratory is evidence about a sample. Whether it can serve as the release document for the batch depends on the framework the batch is released under, which is a question for the quality unit rather than the laboratory.