What a certificate of analysis does not tell you
How to read a certificate of analysis, what a certificate can establish, and the four things it is routinely used to imply but cannot support.
A certificate of analysis records the results of tests performed on a specific batch. Where the tests are appropriate and the laboratory competent, it is a useful record of what that batch measured.
It cannot establish that the tests chosen are the ones that matter, that the batch measured is the batch supplied, that the product is safe or effective, or that any other batch will measure the same. It is routinely used to imply all four, and the gap between what such a document contains and what it is understood to mean is one of the largest in this sector.
What the document is
A certificate of analysis is a record: a list of tests, methods, results and, where a specification exists, the limits the results are compared against. It is issued for a batch and identified by a batch number. In a well run quality system it accompanies release and is one artefact among many.
In this market it frequently appears alone, as the primary technical document supporting a product, and it is asked to carry more weight than its form allows.
The four things it is used to imply
That the right things were tested
A certificate reports the tests performed. It contains no statement that those tests are sufficient to characterise the product. A certificate showing appearance, pH, particle count and sterility is a complete record of four tests and an incomplete characterisation, for the reasons in what a real specification sheet shows.
That the batch measured is the batch supplied
This is a matter of traceability. The certificate carries a batch number; the vial should carry the same number. If a supplier provides a specimen certificate rather than one matching the batch received, the document describes a different batch. That sounds obvious and it is worth checking, because specimen certificates circulate widely as sales material.
That the product is safe
Sterility and endotoxin results address specific hazards. They say nothing about whether the contents provoke an immune response, whether the route of administration is appropriate, or whether the product is lawful for that route. Safety is a conclusion drawn from a body of evidence, not a line on a test report.
That the product works
No certificate of analysis speaks to efficacy. Where a potency assay exists, the result indicates that the batch met the potency criterion, which is a statement about consistency with previously characterised material rather than about clinical effect. In this market potency assays are rare, so most certificates contain nothing bearing on effect at all.
A certificate of analysis demonstrates that a product is safe and effective.
- Proposed mechanism
- Independent laboratory testing verifies the product.
- What has been shown
- A certificate records defined tests on a defined batch. Safety conclusions require an evidence base including adverse event data and route-appropriate assessment. Effectiveness requires clinical evidence. Neither is within the scope of a test report, and most certificates in this sector contain no potency measure at all.
- Highest level reached
- Not shown
- Main confounders
- Specimen certificates presented in place of batch-matched documents. Tests chosen by the party being tested. Absence of a specification against which results are judged.
GradeNOT SUPPORTED
What would change thisNothing about the document. A certificate is the wrong instrument for these claims. Safety and effectiveness require clinical evidence and regulatory assessment, which are different artefacts entirely.
Reading one properly
Six checks, in order.
- Batch number. Does it match the product in hand?
- Date. Manufacture and test dates, and whether they sit sensibly against the expiry.
- Specification column. Are results compared against limits, or reported bare? Bare results mean there is no specification, or it was not shared.
- Methods. Are they named, and are they recognised methods?
- Who tested. The manufacturer, or an independent laboratory? Neither is disqualifying, and the distinction should be visible.
- Scope. What is absent? A certificate without endotoxin for a product used after skin breach has a gap where a relevant test should be.
| Feature | Weak document | Strong document |
|---|---|---|
| Batch identification | Specimen or generic | Batch number matching supplied units |
| Results format | Single values, no limits | Values against stated acceptance limits |
| Methods | Not stated or trade names | Named recognised methods |
| Purity measure | Absent | Particle to protein ratio or equivalent |
| Negative results | None reported | At least one marker or contaminant tested and not found |
| Endotoxin | Absent | Result against a stated limit |
Independent testing, and what it does add
Testing by an accredited independent laboratory adds something real: the party performing the test has no interest in the result. It does not change what the tests can establish. An independent laboratory reporting a particle count has independently reported a particle count.
The strongest version available in practice is an accredited laboratory, testing against a published specification, on a batch identified by number, with methods named. That combination is uncommon and worth noticing when you see it.
What to ask for instead
If the question is what is in this product, ask for the characterisation package and the release specification. If the question is whether it is safe for the intended route, ask for the regulatory status for that route and the adverse event reporting arrangements. If the question is whether it works, ask which clinical studies exist, in which population, with what control and what endpoint, and read them.
Those three requests will not always be met. What they will do is establish quickly whether the supplier holds the material, and that is worth knowing before anything is applied to a patient. Our listings record which of these documents each listed supplier makes available, and which they decline to provide.
Questions readers ask
What is a certificate of analysis?
A document recording the tests performed on a specific batch, the methods used and the results, and where a specification exists, the acceptance limits and whether the batch met them.
Does a certificate of analysis prove a product is safe?
No. It reports results for specific hazards such as sterility and endotoxin where those tests were performed. Safety is a conclusion from a wider evidence base including adverse event data and route-appropriate assessment.
Does it prove the product works?
No. Efficacy requires clinical evidence. Where a potency assay exists, a result shows the batch met the potency criterion, which speaks to consistency rather than to clinical effect. In this market potency assays are rare.
What should I check first?
That the batch number on the certificate matches the product supplied, and that results are reported against acceptance limits rather than as bare values. A specimen certificate describes a different batch.
Is independent testing better?
It removes the interest of the party being tested, which is worth something. It does not extend what the tests can establish. The strongest form is an accredited laboratory testing against a published specification on an identified batch with methods named.