The out-of-range flag is a statistical convention with a printer attached
Almost every misreading of a laboratory panel is a misunderstanding of what a reference interval is and how much a result has to move before the movement means anything.
Laboratory Notebook
Page 10 of 12 of this archive, newest first.
Page 10
Pore size, particle size, and why peptides need the wide pores
A shallow gradient resolves impurities that a steep one runs into the parent peak. Both methods are legitimate; only one of them can see the small stuff.
Reading a barrel in the wrong increments
We have catalogued what readers report, ranked by the size of the dosing error each produces.
The one-quarter rule, and the paper that took it apart
Almost every practical recommendation in circulation was established in a population that does not resemble the people now following it.
Micronutrient monitoring: which panel, how often, and on whose evidence
What the trials measured, which in the case of micronutrients is very little.
What “LC-MS: conforms” tells a reader, which is almost nothing
What the Journal asks for when it writes to a supplier about an identity claim, and how often it gets it.
A lyophilised peptide is not stable. It is slow.
We set out what the cycle does, in order, so that a reader can see which of its steps a rushed operation shortens first.
The figure of merit this trade chose, and the four it did not
Chromatographic purity is cheap, fast and comparable-looking. Those three properties, and not its usefulness, explain why it became the industry’s single figure of merit.
What VendorInvestigate is able to certify about a sealed vial, and what it is not
The Journal has read several hundred certificates from twenty companies. We set out what the documents actually cover, and what a reader is filling in from imagination.
What we are not saying about anybody in this trade
None of what this piece asks for is commercially sensitive, and all of it is already known to whoever released the batch.
Why a dead-clean sterile filter can pass pyrogen straight through
The masking phenomenon known as low endotoxin recovery means a formulation can return a clean result while containing endotoxin the assay cannot see.
How to audit an identity claim in five minutes
The regulated world states the method, the instrument, the convention and the tolerance. This market states a verdict.
Reading HbA1c in the presence of anaemia
A robust, cheap, standardised assay with a specific and well-catalogued set of failure modes, several of which are common in this population.
Two analysts, one chromatogram, two answers
We work through a single chromatogram twice, under two integration conventions, and show where the difference comes from.
Bone density during rapid weight loss: what is known, which is less than you would hope
Weight loss reduces bone mineral density at load-bearing sites. Whether that translates into fractures in this population is unmeasured.
Why the customs shed is the least documented step in this trade
Degradation rates rise exponentially with temperature while an arithmetic mean adds linearly. Mean kinetic temperature is the weighting that reconciles the two, and it is…
What we asked twenty suppliers about stability data
We asked twenty companies three questions about stability data and print every answer, refusal and non-response.
Falling ferritin is not always falling iron
A substantial proportion of the abnormal results generated during rapid weight loss are consequences of the weight loss rather than findings about the person.
Twenty-eight days is a number from somebody else’s product
We set out what is known, what is inferred and what is simply assumed about the fortnight after a vial is opened.
Why the bone question is harder than the muscle question
What the Journal would want measured before treating this as settled in either direction.