Every letter we have printed

You describe the low-T3 pattern during energy restriction as benign adaptation. There is a body of opinion holding that it represents a genuine hypometabolic state requiring treatment. I do not hold that view but your readers will encounter it.

A modest addition to your list: anything present below the detection limit. It is obvious when stated and it is routinely forgotten, because a clean spectrum reads as a clean sample. The absence of a peak is a statement about sensitivity before it is a statement about composition.

Aspartate isomerisation changes nothing about the mass at all. Nor does racemisation of a single residue. Both alter the molecule in ways that a chromatographic method developed for the purpose can sometimes resolve, and that a mass measurement cannot see under any circumstances.

I have spent a week trying to reconcile a certificate’s stated mass of 4113.6 with a figure of 4111.1 I calculated from the sequence, and had convinced myself something was wrong with the vial. It was the isotope convention. Thank you, and also: how is this not stated on every certificate in existence?

You write that leucine and isoleucine cannot be distinguished by tandem mass spectrometry. That is too absolute. Side-chain fragmentation under high-energy conditions produces diagnostic w and d ions, and the discrimination has been demonstrated repeatedly.

You give the glutamine-to-lysine difference as 0.036 daltons and say it needs an orbital trap. In practice you also need the two species to be chromatographically separated or present in a sensible ratio, because at one per cent of the parent intensity the minor peak sits on the shoulder of the isotope envelope regardless of resolving power.

Publishing the individual-level scatter rather than the group means would transform this literature. The means are compatible with several very different underlying distributions and the scatter would distinguish them immediately.

Prespecification matters here more than usual. A composition endpoint added after the parent results were known is a different kind of evidence from one written into the protocol, and the papers do not always make clear which they are reporting.

Community calculators are widely used and almost none of them show their working. A tool that produces a number without the intermediate steps cannot be checked, and the checking is the part that catches the error.

Rounding conventions differ between calculators and the differences are not trivial at small volumes. Two tools given identical inputs will return different answers, and neither will say which convention it used.

I have accumulated about eighteen months of used needles in a plastic tub because I did not know where to take them and assumed I would be asked questions. Your paragraph on this is the first time I have seen the situation described rather than lectured about.

I would like to see the phrase "area normalisation" appear on certificates that use it. It is not a defect; it is a method with a stated assumption, which is that everything present absorbs equally at the detection wavelength. The assumption is false for peptides and the arithmetic proceeds regardless.

Our practice is to require the chromatogram alongside the number, and the striking thing is how often the request is met and how rarely anyone makes it. Two years of asking and we have been refused twice. The data is sitting on a laboratory server that nobody is querying.

Your worked example varies gradient and threshold together and reports a 1.8-point spread. Which of the two contributed more? The article does not say, and the answer matters for what you are asking suppliers to disclose first.

Your submission design has a hole in it. Eight vials from one lot cannot separate variation between laboratories from variation between vials, because you have no replicate within a laboratory to estimate the second. Two vials each is a start and it is not enough, and the honest conclusion from your table is that the four figures differ, not that the laboratories do.

Accreditation is worth less than buyers think and more than your article allows. A scope certificate tells you the laboratory has been audited for the methods listed on it, and nothing about whether your sample was run under one of them. Ask for the scope, then ask whether your test sits inside it.

A unit is not a dose and the word does the damage. It is a mark on a barrel. What it corresponds to in milligrams depends entirely on the concentration in the vial, and two people using the same mark on the same syringe can be drawing quantities that differ several-fold.

The stated content of a vial is the assumption everything else rests on, and it is exactly the quantity this publication has shown is least often independently determined. The arithmetic can be perfect and still produce the wrong answer.

Designing the error out is more effective than warning about it, which is the settled conclusion of every human-factors literature. In this market nobody controls the design, so the only available lever is the weakest one.

My objection is narrower than most of your correspondents’. I do not mind an undated badge on a page about a company. I mind an undated badge beside a price, because the proximity makes a claim about that product which nothing in the mark supports.

A translation problem worth noting: many buyers in this market read these pages in a second language, and an image survives translation where a paragraph of qualification does not. The badge is therefore doing more work for exactly the readers least able to interrogate it.

Custody protects the supplier at least as much as the buyer. A result produced from a sample of unknown history is not evidence against anybody, and suppliers who understand that ought to be the loudest advocates for the practice.

The mechanistic account is assembled from studies in different species, at different exposures, on different endpoints, and it is presented as one continuous story. Each join in that chain is an inference and none of them is flagged.

Baseline variation in transit time across a healthy population is wide enough to swamp small effects, and studies with modest sample sizes are therefore measuring a difference against a very noisy background. Confidence intervals in this literature are wide for good reasons.

An image is a poor container for a conditional statement. Everything interesting about a determination is conditional — on the sample, the method, the date — and none of it survives compression into a graphic. The format has selected the message.

What a badge cannot do is carry forward in time. A report on a lot filled eighteen months ago says nothing about the lot shipping today, and the badge sits in the page template rather than on the product. Verification has a date and the design of these things hides it.

A caution on cross-molecule potency comparisons. Milligram-for-milligram statements between agents with different receptor profiles and different half-lives are close to meaningless, and they are the commonest error I see in general coverage. Your department avoids them, which is why I read it.

Adding glucagon agonism to increase energy expenditure is elegant and it is also the limb that has to be balanced most carefully, because the same receptor raises hepatic glucose output. The ratio between the components is the whole design problem and it is quoted far too casually.

Trial populations were selected, monitored and supported in ways that the general population is not, and event reporting in a trial is systematic in a way that reporting outside one never is. Both facts push the comparison in opposite directions and neither is usually mentioned.

The most useful presentation I have seen was a cumulative curve rather than a proportion, because it showed both how many and when. It is not harder to produce and it is almost never chosen.

The central and peripheral contributions are separable in animal work and not in human studies, and coverage tends to attribute everything to whichever the writer finds more intuitive. The honest statement is that both are implicated and the proportion is unknown.

The anaesthetic guidance in this area has moved considerably in a short time and the versions circulating are not all current. A publication reporting on it should date the guidance it describes, because a reader acting on a superseded version is acting on something that has been withdrawn.

Whoever decided that a piece should say what it does not allege deserves credit. That paragraph does more to keep the argument honest than any amount of hedging elsewhere.

A stated storage condition without a supporting stability study is a recommendation rather than a finding, and the two look identical on a label. The question to ask is not what the storage condition is but what data it rests on, and the answer separates the trade quite sharply.

The customs hold is the invisible leg. A parcel detained for four days has a thermal history nobody records, and the only trace of it is a gap in the tracking that most buyers never look at.

You say no company reports residual moisture. I obtained a figure from a supplier last year without difficulty, on request, so the data exists in at least some cases. The problem may be less that it is not measured than that it is not printed.

Concentration matters for solution stability and it is chosen by the person reconstituting rather than by anybody who has studied it. A dilute preparation and a concentrated one are two different experiments, and both are described by the same anecdote.

Degradation products are not inert and the literature on them is thin for most sequences in this market. A discussion of purity that only counts what is lost, and never asks what it became, is half a discussion.

Your list of twelve method values omits the equilibration time between injections. On a shallow gradient with an aqueous-rich starting composition, an inadequate re-equilibration will shift early-eluting impurities into the solvent front and quietly remove them from the denominator. It is the cheapest way to improve a figure by accident.

You treat the column as a single value. In practice it is three: the stationary phase, the particle and pore dimensions, and the age of that particular column. The third is the one that moves results between two laboratories quoting the same part number, and no certificate has ever recorded it.