On the subject in the title: The decimal-point error, and the habit that catches it Working notes rather than a conclusion.
A follow-up question about decimal-point error that I did not know to ask the first time.
The earlier thread answered what I asked. What I should have asked is below, and I think it is the one that matters.
If someone has run decimal-point error properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
The opening post describes the usual case. This is about the unusual one.
Agreed on decimal-point error, with one qualification that I think matters. The reasoning holds for the case as described. Change the starting assumption and it does not, and the starting assumption is the part nobody states.
Building on post #2 rather than restating it.
The decimal-point error: computing 5 mg / 2 mL as 0.25 mg/mL instead of 2.5 mg/mL is the most common arithmetic error in this subcategory. The habit that catches it: writing the units in every step of the calculation.
Post #4 put the caveat in the right place and I want to underline it.
Reading back through the decimal-point error threads from last year, the same three questions come up every time and only one of them has ever been answered properly. That seems like a documentation gap rather than a knowledge gap.
Grateful for the specificity. Vague answers to this question are what sent me looking.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
I had written a reply contradicting post #7 and deleted it. Here is what survived.
I disagree with the framing of decimal-point error above, and I think it is a substantive disagreement rather than a terminological one. Setting out why, so it can be checked.
The reasoning depends on an assumption that is doing a lot of work and is never stated. If the assumption holds, the conclusion follows. I do not think it holds generally.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
A request rather than an answer: could whoever has the primary source for decimal-point error post it? I have seen the claim three times this month and each version had lost a qualifier.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
Thank you for the correction. I would rather find out here than later.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
A single observation, in a thread that deserves better than single observations.
The arithmetic in post #15 is right; the assumption feeding it is the part to check.
Where the decimal-point error discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are the same sentence with different clothes on.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
I would put the burden of proof on the interesting explanation, not the dull one.
Confirming post #20 from a second method, which matters more than confirming it from a second person.
Decimal-point error has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
I am aware this is the third time this month I have made this point.
Post #22 describes the usual case. This is about the unusual one.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
This is the version I would want a new member to read first.
Post #24 is right about the mechanism and I think understates the practical bit.
An observation about decimal-point error that I cannot explain and am posting anyway, on the principle that unexplained observations are more useful public than private.
Coming back to post #22, because the follow-up matters more than the original answer.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
I have separated what I observed from what I concluded, which does not always happen.
Write the reconstitution date and the concentration on the vial. Not on a note, on the vial. Every account here of a dosing error involving the wrong concentration involves a vial with nothing written on it.
A weak preference rather than a position.
I would be cautious about generalising from the decimal-point error example above. It is a good example. It is one example.