Every letter we have printed
Page 77 of 93 of this archive, newest first.
On “Grams per kilogram of what? The denominator problem in protein guidance” — Clinical Trials, 17 Jun 2024
Intake relative to body mass changes during the study even when absolute intake is constant, and papers differ on which they report. The two produce different-looking results from identical data.
— C. Rijkaard, Groningen
On “The four testing services and the study none of them can run” — Analytics, 17 Jun 2024
I asked a supplier for the shipping validation behind their stated pack and received a two-page summary with a temperature profile and a duration. It took four days. The document existed the whole time and nobody had ever requested it, which is the pattern your reporting keeps finding.
— L. Dziedzic, Wrocław
It is the pattern, and it is the most encouraging thing in this subject. A great deal of what buyers want already exists and is simply never asked for.
On “The four testing services and the study none of them can run” — Analytics, 17 Jun 2024
Packing configuration should be documented and almost never is. The number and placement of the coolant packs determines how long a parcel holds temperature far more than the quantity of insulation, and it varies between consignments from the same supplier.
— S. Weatherall, Newcastle, NSW
Configuration is the variable that changes silently between shipments, and it is one of the few a buyer can ask about and get a straight answer on.
On “The four testing services and the study none of them can run” — Analytics, 17 Jun 2024
The last mile is the part nobody controls and the part that fails. A parcel can travel refrigerated for six thousand miles and then sit in a delivery van in July for eleven hours, and the pack was specified for the journey the shipper planned rather than the one that happened.
— H. Barreto, Recife
Almost every excursion in our own logger data has landed in the final forty-eight hours. The long leg is engineered; the short one is improvised.
On “Adsorption, and the dose that stayed on the glass” — The Supply Chain, 16 Jun 2024
In-use stability is where the real losses happen and where there is least data. A dry powder is forgiving; the same peptide in solution at room temperature is not. Every practical question a buyer has begins at the moment the diluent goes in, and the documentation stops at the moment before.
— N. Aftab, Lahore
That gap between what is documented and where the risk sits is the theme of the whole department, and this is its sharpest instance.
On “Adsorption, and the dose that stayed on the glass” — The Supply Chain, 16 Jun 2024
In-use figures quoted in this market trace back, when you follow them, to manufacturer statements about a different formulation of a different product. The chain of citation is worth publishing on its own.
— D. Ramkissoon, Port of Spain
On “Adsorption, and the dose that stayed on the glass” — The Supply Chain, 16 Jun 2024
You treat aggregation as a degradation pathway alongside the chemical ones. It is worth separating, because it is physical, it is often reversible in principle and irreversible in practice, and it is the one pathway that reversed-phase chromatography will not report on at all.
— R. Sundaresan, Coimbatore
Agreed, and the piece would be clearer for the split. Chemical routes change the molecule; aggregation changes what the molecules are doing to each other.
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Explainers, 15 Jun 2024
Of the documents I have from companies in your dossier programme, the better ones state the observed mass alongside the theoretical value and name the instrument class. That is the standard the rest of the trade could meet tomorrow, and the fact that some suppliers already meet it is the useful part of your reporting.
— S. Tovmasyan, Gyumri
It is, and it is the reason this programme reports what the good documents contain rather than only what the poor ones omit. The convention is achievable because it is already being achieved.
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Explainers, 15 Jun 2024
A mass spectrum reproduced at postage-stamp size in the corner of a certificate is decoration rather than evidence. If the document is going to carry the spectrum, it should carry it at a size where the isotope pattern is readable, or it should carry the data file reference instead.
— J. Kettleborough, Nottingham
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Explainers, 15 Jun 2024
Your piece treats the source as a fixed component. It is a consumable with a maintenance history, and a fouled source changes response for some compounds far more than others. Ask when the source was last cleaned, and you will occasionally learn more than the spectrum tells you.
— O. Brannigan, Galway
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Explainers, 15 Jun 2024
Water is the invisible component nobody costs. A lyophilised cake that has taken up moisture in a warm warehouse weighs more and delivers less, and the purity figure is entirely unaffected because it is a ratio of peak areas. Two vials, same certificate, different dose.
— J. Marsden-Hoyle, Halifax
On “The badge economy, and what it is actually certifying” — The Ledger, 14 Jun 2024
A defence of the practice, since you have printed several attacks. Before badges existed there was no public evidence of any testing at all. The current arrangement is a poor version of a good idea and it is still an improvement on what preceded it.
— D. Iversen, Aalborg
We agree and the piece says so. The criticism is of a mature practice that has stopped improving, not of the impulse that created it.
On “The badge economy, and what it is actually certifying” — The Ledger, 14 Jun 2024
I run a laboratory that issues these reports and I read your criticism as fair. What we control is the document; what happens to our logo afterwards is outside our sight entirely. We would welcome a convention that let us take it back.
— A. Wiśniewski, Szczecin
On “Micronutrient monitoring: which panel, how often, and on whose evidence” — Laboratory Notebook, 14 Jun 2024
The published trials in this class collected some of this data and reported very little of it, which is a genuine gap rather than a negative finding. It should be described as unreported rather than as unchanged.
— D. Oyelaran, Oshogbo
On “Micronutrient monitoring: which panel, how often, and on whose evidence” — Laboratory Notebook, 14 Jun 2024
Vitamin B12 status is imperfectly captured by a serum level, and the confirmatory markers are available and rarely ordered. Where the question genuinely matters, the serum value alone is the weakest form of the answer.
— N. Aftab, Lahore
On “Sarcopenia is a diagnosis, not a synonym for losing lean mass” — Patient Notes, 13 Jun 2024
Rate of change is the variable most likely to modify the ratio and the one least often reported alongside it. Two studies with the same endpoint and different trajectories are not measuring the same thing.
— S. Rajapaksa, Colombo
On “Sarcopenia is a diagnosis, not a synonym for losing lean mass” — Patient Notes, 13 Jun 2024
Extrapolation beyond the study horizon is the quietest error, because it produces no obvious absurdity. A ratio observed over sixty-eight weeks says nothing about year four, and it is routinely applied to indefinite horizons.
— J. Kettleborough, Nottingham
On “Sarcopenia is a diagnosis, not a synonym for losing lean mass” — Patient Notes, 13 Jun 2024
Bone density changes lag soft tissue changes by months, so a scan taken at the end of a rapid loss period is measuring a skeleton that has not finished responding. Interpreting it as a final result is a timing error rather than a measurement one.
— H. Okwuosa, Enugu
The lag is the reason a single post-intervention scan answers a narrower question than it appears to.
On “Rapid weight loss moves eight analytes for reasons that have nothing to do…” — Patient Notes, 13 Jun 2024
Pre-analytical variables account for far more surprising results than laboratory error does. Fasting state, posture during the draw, tourniquet time and the interval before separation all move numbers, and none of them appears on the report.
— G. Enríquez, Quito
None of them appears, and a repeat draw under controlled conditions resolves a great many anomalies without any further investigation at all.
On “Rapid weight loss moves eight analytes for reasons that have nothing to do…” — Patient Notes, 13 Jun 2024
Tube type and fill volume matter. An underfilled tube changes the ratio of sample to additive, and the result is affected in a direction that depends on the analyte. The laboratory notices; the person receiving the report usually does not.
— T. Kirchner, Hamburg
On “Stepping down against stopping: two decisions treated as one” — Clinical Trials, 12 Jun 2024
What a gradual reduction may do is provide a period in which habits are established while some effect remains, which is a behavioural rationale rather than a pharmacological one. Stating which kind of rationale is on offer would clarify a confused discussion.
— A. Lindholm, Gothenburg
A behavioural rationale honestly labelled is worth more than a pharmacological one asserted, and the two are constantly conflated here.
On “Stepping down against stopping: two decisions treated as one” — Clinical Trials, 12 Jun 2024
Whatever is decided, the most useful thing anybody can do is write down the date of the last dose and what happened over the following weeks. The observational record in this area is poor mainly because nobody keeps one.
— P. Hollingsworth, Norwich
On “Stepping down against stopping: two decisions treated as one” — Clinical Trials, 12 Jun 2024
The pharmacokinetic argument for and against intermittency is at least tractable from published data, even where clinical outcomes are not. A piece that worked through the exposure arithmetic without drawing clinical conclusions would fill a real gap.
— K. Ndlovu, Bloemfontein
On “What VendorInvestigate charges to answer the pyrogen question” — The Supply Chain, 11 Jun 2024
Storage does not reduce endotoxin. It is thermally stable well beyond anything a domestic process would apply, and the intuition that time or cold will help is entirely wrong here.
— J. Verstraete, Bruges
On “What VendorInvestigate charges to answer the pyrogen question” — The Supply Chain, 11 Jun 2024
Your explanation of endotoxin units is the clearest I have read outside a pharmacopoeia, and the unit is where most confusion starts. A limit expressed per milligram and a limit expressed per container are different constraints, and which one applies depends on how much material is used at once.
— A. Mbeki, Lusaka
Per milligram, per millilitre and per container are three different statements, and a report quoting one of them without saying which is not usable.
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Laboratory Notebook, 10 Jun 2024
Of the documents I have from companies in your dossier programme, the better ones state the observed mass alongside the theoretical value and name the instrument class. That is the standard the rest of the trade could meet tomorrow, and the fact that some suppliers already meet it is the useful part of your reporting.
— S. Tovmasyan, Gyumri
It is, and it is the reason this programme reports what the good documents contain rather than only what the poor ones omit. The convention is achievable because it is already being achieved.
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Laboratory Notebook, 10 Jun 2024
The identity section I would accept contains four things: theoretical mass, observed mass, which mass convention was used, and the instrument. Three of the four cost nothing to print. Every certificate I hold from the wider market carries one of them.
— C. Waterston, Carlisle
Four lines is the right length for that section and it is a good deal shorter than the disclaimer most certificates carry beneath it.
On “What “LC-MS: conforms” tells a reader, which is almost nothing” — Laboratory Notebook, 10 Jun 2024
The leucine and isoleucine problem is the cleanest illustration of your argument. They are the same mass, they are different residues, and no amount of accuracy on the intact molecule will separate them. Sequence confirmation requires fragmentation and, for that particular pair, a fragmentation method most services do not run.
— G. Papadakis, Thessaloniki
It is the example we now use whenever somebody says a mass match confirms a sequence. Two structures, one mass, and an instrument that is behaving perfectly.
On “Reflux, early satiety, and the volume the stomach will accept” — Patient Notes, 8 Jun 2024
Emptying rate and symptom intensity correlate poorly at the individual level, which is one of the more interesting findings in the area. It means the mechanism is necessary and not sufficient, and coverage that treats them as the same thing is misleading.
— T. Björnsson, Akureyri
The weak individual-level correlation is the finding that most complicates the simple mechanistic story, and it is exactly the sort of result that disappears from secondary accounts.
On “Reflux, early satiety, and the volume the stomach will accept” — Patient Notes, 8 Jun 2024
Constipation and diarrhoea both appear in the same tables and they are not the same phenomenon at all. Grouping them as gastrointestinal events obscures that motility is affected in more than one place and in more than one direction.
— L. Fontaine, Brussels
On “Adverse events by dose, adverse events by week” — Pharmacology, 6 Jun 2024
The placebo arm rates are substantial and almost never quoted, which makes the active arm figures look more dramatic than the comparison supports. The difference between the arms is the finding; the raw active figure is the headline.
— A. Wiśniewski, Szczecin
On “Adverse events by dose, adverse events by week” — Pharmacology, 6 Jun 2024
Incidence figures from placebo-controlled trials should always be quoted with the placebo arm beside them, and in secondary coverage they almost never are. The difference between arms is the finding; the raw proportion is not.
— K. Sivertsen, Bergen
Quoting the active-arm rate alone is the most common error in coverage of this literature and it inflates every figure it touches. We print both arms as a rule.
On “Adverse events by dose, adverse events by week” — Pharmacology, 6 Jun 2024
Nobody publishes the distribution, only the proportion. Whether effects are mild across most of a population or severe in a small part of it is the question a reader has, and an incidence figure cannot answer it either way.
— B. Wojciechowski, Kraków
On “Adverse events by dose, adverse events by week” — Pharmacology, 6 Jun 2024
A protocol that permits both dose reduction and delay produces a tolerability figure describing a population that used those options. The figure is real and it is not a statement about the nominal schedule.
— H. Okwuosa, Enugu
On “Adverse events by dose, adverse events by week” — Pharmacology, 6 Jun 2024
A note of thanks from a long-standing reader who has never written before. The consistency across thirty issues is the thing worth remarking on, and consistency never gets a letter.
— S. Tovmasyan, Gyumri
On “A lyophilised peptide is not stable. It is slow.” — Laboratory Notebook, 5 Jun 2024
Residual moisture and cake structure are set by the freeze-drying cycle, which is a manufacturing parameter nobody in this market ever asks about. It determines the stability of everything downstream of it.
— B. Novotný, Ostrava
On “A lyophilised peptide is not stable. It is slow.” — Laboratory Notebook, 5 Jun 2024
Stopper choice belongs in this section. A stopper that has not been properly dried will release water into the headspace over months, and a cake that left the plant at one per cent moisture will not still be at one per cent when it arrives. The container is part of the formulation.
— D. Chukwuma, Onitsha
On “A lyophilised peptide is not stable. It is slow.” — Laboratory Notebook, 5 Jun 2024
Dispatch day matters more than packaging. A parcel posted on a Thursday afternoon spends the weekend in a depot, and no amount of insulation is specified for that. Ask what day a shipment leaves, and if the answer is late in the week, ask them to hold it.
— P. Hollingsworth, Norwich
On “A lyophilised peptide is not stable. It is slow.” — Laboratory Notebook, 5 Jun 2024
Agitation matters. A vial carried in a bag for a day has experienced mechanical stress that a vial on a shelf has not, and interfacial stress is a recognised cause of aggregation in protein preparations generally.
— J. Kiptoo, Eldoret
On “A lyophilised peptide is not stable. It is slow.” — Laboratory Notebook, 5 Jun 2024
The mean kinetic temperature explanation is the clearest I have read anywhere, including in the training my employer paid for. I have printed the sidebar and put it on the wall of the dispatch room.
— E. Marchetti, Bologna