Vol. 3, No. 6 — June 2026Independent since 2024

TheCompound Journal

Reporting on incretins, compounding & the peptide supply chain

A monthly journal of record.
30 issues · 32 contributors
Not medical advice. We sell nothing.

Documents

Specification and result are two columns, and only one of them is a measurement

The arithmetic of significant figures, applied to a document that routinely reports four of them.

“Conforms” is the most consequential word in this trade and it is almost always unaccompanied. Conforms to what? Measured how? Against which limit, applied under what rule about measurement uncertainty? The accreditation framework governing testing laboratories is explicit that a statement of conformity requires a documented decision rule — the policy determining whether a result sitting close to a limit is reported as a pass — precisely because the word otherwise conceals a judgement rather than reporting a measurement.

The test table: four columns, and most certificates carry two

The body of a certificate is a table, and a complete one has four columns: the test performed, the method used, the specification applied, and the result obtained. Four columns, one row per test. That structure is not a convention peculiar to pharmaceuticals; it is what a record of controlled testing looks like in any field, because each column answers a question the other three cannot.

The method column is where the detail belongs — not the word HPLC but a method identifier, a gradient, a wavelength, a column chemistry. The specification column states what the batch had to achieve. The result column states what it did. A certificate carrying only test and result has dropped the two columns that make the result interpretable, and this is by far the commonest structural deficiency the Journal encounters.

The compendial framework for validating an analytical procedure exists precisely to establish that a stated method can discriminate what it claims to discriminate, which is why a method reference is not bureaucratic ornament but the hook on which everything else hangs.12 A named method can be looked up, compared, criticised and repeated. An unnamed one cannot be, and a result generated by one is a number whose provenance stops at the page.

The two columns, and why both are needed

Consider a certificate reporting a purity of 98.6%. Without a specification, that number cannot be assessed: it may be well within a limit the manufacturer routinely meets, or it may be a marginal pass against a limit of 98.5% that the batch scraped through. Those are materially different situations for a buyer, and the difference is precisely what the specification column exists to record.

Now consider the reverse: a certificate stating a specification of “≥98.0%” with the result given only as “conforms”. Here the reader knows the criterion and not the measurement, which is arguably worse, because a result of 98.1% and a result of 99.8% both conform and the second says something about process control that the first does not. Both columns are necessary because they answer different questions: the specification asks what was promised, the result asks what happened.

Specifications and acceptance criteria for a biotechnological article are set out in the international guidance as a defined list of tests with defined limits, precisely so that a release decision is reconstructible after the fact.3 The research-grade certificate has inherited the vocabulary of that framework — the word specification appears, the word conforms appears — without the substance, and the vocabulary is doing rhetorical work the underlying documentation does not support.

A specification is a commitment made before the test. A result reported without one is a commitment made afterwards.

What “conforms” conceals

A statement of conformity is a judgement, not a measurement, and the judgement depends on how the reporting party handles results that sit near a limit. If a specification requires not less than 98.0% and a measurement returns 97.9% with a method uncertainty of ±0.4%, does the batch conform? The answer depends entirely on a policy — whether the limit is applied to the measured value, or to the measured value adjusted for uncertainty, and in which direction. Metrological reporting practice has a settled answer here, which is that a result quoted without its uncertainty cannot be compared to a limit at all.4

The accreditation standard for testing laboratories requires that where a statement of conformity is given, the decision rule employed is documented and the report identifies it.5 This is not a technicality. Without a decision rule, “conforms” means whatever the person writing it decided it meant on the day, and two laboratories applying different rules to the same measurement will report different verdicts without either being wrong.

In this market decision rules are essentially unknown, and the practical consequence is that the word carries no information about marginal cases. The Journal therefore reports numbers rather than verdicts wherever a number is available, and where a source supplies only a conformance statement we say so explicitly rather than paraphrasing it as a pass. Readers occasionally find this pedantic. It is the difference between reporting a measurement and repeating an opinion.

Which elements appear on twenty suppliers’ certificates
ElementCertificates carrying it (of 20)
Product name and batch number20
Purity result20
Date of analysis18
Identity test of any kind14
Appearance13
A name in the signature block11
Date of manufacture10
Specification column present for all tests9
Named method with gradient or wavelength7
Sequence printed in single-letter code6
Retest or expiry date with convention stated5
Water content4
Peptide content3
Counter-ion identity and content2
Two signatures in the regulated pattern2
Statement linking bulk lot to fill lot3
Counts are of the most recent certificate supplied to the Journal by each of the twenty companies in the dossier programme, at the last quarterly cycle. Several companies supply additional information on request that does not appear on the standard document; those cases are credited here only where the element appears on the certificate itself.

The specification that cannot be failed

There is a class of acceptance criterion which is technically present and practically inert, and once you have learned to see it you will find it everywhere. A purity limit of ≥95% on material the supplier consistently reports above 99%. A mass tolerance of ±1 dalton on a peptide of four thousand daltons, which corresponds to two hundred and forty parts per million and would be met by essentially any instrument. An appearance specification of “powder”. A water specification of “≤10%” on a material that typically carries three.

None of these is a false statement and none is evidence of bad faith. They are the residue of forms designed for a broad catalogue, where a single specification has to cover hundreds of products with different behaviours, and where the limit is set at the point below which the supplier would definitely intervene rather than at the point representing normal performance. Distinguishing between the two is the whole art of reading the specification column.

The useful question to ask of any limit is what the supplier’s typical result is. A specification of ≥98% with results clustering at 98.2% is a real control operating close to its edge. A specification of ≥95% with results at 99.4% is a wide net around a well-behaved process. Both are defensible; they mean different things; and a buyer who reads only the result learns neither. The pharmacopoeial convention is worth holding on to here: a specification states the quality a substance must possess, not a complete description of what it is.6

How this publication handles certificates

Four rules, arrived at over two years and revised twice. First, we do not cite a purity figure without the method behind it; where a supplier will not supply the method, we report the figure as unverifiable and say who declined. Second, we ask for the underlying laboratory report rather than the certificate, and we record who supplies one. Third, we check the accreditation scope of any laboratory named on a document we intend to rely on. Fourth, we put every documentary finding to the company concerned before publication and print the response in full.

The fourth rule is the one that has changed our coverage most. A substantial majority of the anomalies we find turn out to have mundane explanations: a transcription error, a document forwarded for the wrong lot, a template field left unedited, a scanned copy that lost its metadata. Publishing the finding without the explanation would have produced a series of insinuations rather than a series of corrections, and the corrections are more useful.

The rules also mean we publish less than we could. There are documents in this office that we consider unreliable and have not written about, because the company concerned did not respond and the finding alone would not support a published inference. That is a deliberate trade, and readers who suspect us of excessive caution are welcome to say so at letters@compoundjournal.com, where several already have.

2116115.3019No vial batch…17No spec column16Method as acr…13No mfg date11No signed name9Unsupported e…3MW vs sequence2Repeated tracecertificates of 63
Figure. Documentary findings across 63 audited certificates, with the number resolved after the Journal put the finding to the company concerned. Most are administrative rather than analytical.

A necessary distinction between a bad document and a bad product

Almost nothing in this article supports an inference about the contents of a vial. A certificate missing a specification column, an unsigned footer, a stale date of analysis and a batch number that appears only on the carton is a poor document. The material it accompanies may be excellent, and in the Journal’s experience frequently is: the analytical work behind these products is often better than the paperwork that reports it, because the paperwork is produced by a commercial function and the analysis by a laboratory.

The reverse also holds. A beautifully constructed certificate with four columns, two signatures and a named method is evidence of a functioning documentary process and is not evidence about the vial either, since a document cannot testify to material it does not accompany. This is why the Journal reports documents as documents and material as material, and declines to convert one into a claim about the other.

We labour the point because the alternative is a genre of coverage that treats documentary weakness as proof of dishonesty, and that genre is both unfair and useless. Unfair because most documentary weakness in this trade is inherited convention rather than intent. Useless because it gives a reader nothing to do. Reading the document properly gives a reader something to do, which is the entire purpose of this piece.

The Journal will keep asking the twenty companies in its dossier programme for the same seven lines each quarter, and will keep publishing who supplies them. Two years of doing this has produced measurable movement: the number of programme certificates carrying a specification column for every test has risen from four to nine, which is slow and is not nothing.

References

  1. United States Pharmacopeia. General chapter ⟨1225⟩, Validation of Compendial Procedures. USP–NF.
  2. International Council for Harmonisation. Q2(R2): Validation of Analytical Procedures. 2023.
  3. International Council for Harmonisation. Q6B: Specifications — Test Procedures and Acceptance Criteria for Biotechnological/Biological Products. 1999.
  4. “Measurement uncertainty, significant figures and the reporting of chromatographic purity.” Analytical Chemistry. 2018;90(3):1476–1484.
  5. International Organization for Standardization. ISO/IEC 17025:2017, clause 7.8.6, “Reporting statements of conformity,” on the requirement to document and identify the decision rule applied.
  6. European Directorate for the Quality of Medicines. European Pharmacopoeia, General Notices, on the status of specifications and the demonstration of compliance. Strasbourg.

Letters to the Editor

3 printed

Selected from correspondence received on this article. Writers are identified by initial, surname and city, verified before printing. Replies are from the desk that filed the piece or from the standards editor. Write to letters@compoundjournal.com.

You describe reused chromatogram images as a tell. I work in a contract laboratory and I would note that some data systems export a representative overlay rather than the individual injection, so identical-looking traces can occur legitimately across a batch series. It is still worth asking about; it is not the smoking gun your article implies.

D. Ramkissoon, Port of Spain

The Journal replies

A useful qualification and the text has been softened. The observation remains worth making; the inference we drew from it was stronger than the practice supports.

Your ten-minute check told me in about ninety seconds that the batch number on my certificate appears nowhere on the vial. I wrote to the supplier and had a straightforward answer within a day: the certificate covers the bulk lot and the vial carries a fill code. I would never have known to ask.

P. Kovalenko, Lviv

The Journal replies

That is exactly the intended use, and the supplier’s answer is the correct one. The remaining question is why the relationship between the two codes is not printed on the document, since it takes a line.

I have a certificate with an expiry date twenty-four months from manufacture and no stability data behind it, which your article says is a claim the documentation cannot support. The supplier tells me it is industry standard. Is it?

C. Adeoti, Ibadan

The Journal replies

Twenty-four months is a common default and “industry standard” is an accurate description of the practice rather than a justification of the claim. The distinction we would press is between an expiry date, which asserts shelf life, and a retest date, which asserts only a review interval. The second is defensible without stability data. The first is not.

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