A guide to the results that will resolve themselves
The panel drawn during a week of vomiting is measuring the vomiting.
Laboratory Notebook
Page 8 of 12 of this archive, newest first.
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What changed after we published the first version of this
A reader holding a certificate can work out what it does not cover in about ninety seconds, and that is a useful ninety seconds.
What happens in solution that does not happen in the cake
Every degradation pathway accelerates by orders of magnitude on reconstitution, because the solvent that lyophilisation removed is the reagent most of them need.
What the older diet-and-exercise trials found in the hip
Weight loss reduces bone mineral density at load-bearing sites. Whether that translates into fractures in this population is unmeasured.
The question no chromatogram has ever answered
Purity, content, identity, sterility and endotoxin are five separate determinations. A single sheet of paper carrying one of them is not evidence about the other four.
The reproducible spectrum: the single most useful thing a report can carry
None of what a checkable identity statement requires is commercially sensitive, and all of it is known to whoever produced the document.
The out-of-range flag is a statistical convention with a printer attached
A flag is a probability statement about a population. It is not a statement about the person holding the printout.
Sarcopenia is a diagnosis, not a synonym for losing lean mass
The gap between a defensible recommendation and a confident one is where most of the harm in this subject lives.
The supplement trade found this drug class quickly, and the citations did not improve
A survey of what the meta-analyses support, with the populations named.
Two sessions a week, and the evidence behind the prescription
The recommendation survives scrutiny. The reasoning offered for it frequently does not.
The retest date and the expiry date are not the same document
We asked twenty companies three questions about stability data and print every answer, refusal and non-response.
Two sessions a week, and the evidence behind the prescription
The recommendation survives scrutiny. The reasoning offered for it frequently does not.
What a mass spectrometer does to a peptide before it measures anything
A brief and unromantic tour of the interface between a liquid sample and a vacuum.
Mapping a rotation that you will actually follow
Repeated injection into the same small area produces lipohypertrophy — thickened, rubbery subcutaneous tissue with blunted and erratic absorption. It is common, it is…
A part per million, in context
Every instrument specification quoted in an advertisement is a best case obtained on a calibration mixture, not on a submitted vial.
What Medutest can tell you about a vial by weighing its water
Water is a reactant in hydrolysis, a plasticiser that mobilises the amorphous matrix, and a carrier for everything else. All three matter.
The certificate is silent on contamination, and it never claimed otherwise
Every certificate circulating in this market answers a question about molecules. Almost none answers a question about organisms, pyrogens, or the integrity of the seal.
Set the threshold at a tenth of a per cent and the small impurities vanish
Baseline placement under a tailing peak is a judgement call with a direct effect on the area. It is one of the few places where two competent analysts genuinely disagree.
What Sweden customs does to a parcel it has decided to examine
A gel pack has a finite thermal budget, and once it is spent the payload equilibrates with whatever is outside the box. The only question is how long that takes.
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.