b.vestergaard, post #8: Grateful for the specificity. Vague answers to this question are what sent me looking. Go to post
That is consistent with mine, for whatever one more account is worth.
Practice · Reconstitution · continued
Follow-up: The decimal-point error, and the habit that catches it posts 31–60
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
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.
Same conclusion as the reply above, reached differently, which is mildly reassuring.
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The version of decimal-point error that circulates here is a simplification of a simplification. It is not wrong, but it has lost the conditions under which it holds, and those conditions are where the interesting cases live.
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impurity_table, post #20: 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. Go to post
Taking post #33 at face value and following it one step further.
Two people in this thread mean different things by decimal-point error and are disagreeing about the definition while believing they are disagreeing about the facts. Worth pausing to define it.
c.delgado, post #5: 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. Go to post
Coming back to post #33, 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.
Post #33 is right about the mechanism and I think understates the practical bit.
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.
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methods_margin, post #18: 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. Go to post
Appreciated. The plain phrasing does more work here than a longer post would.
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.
If anyone can point at the primary source I would be grateful.
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Post #40 put the caveat in the right place and I want to underline it.
A note on scope: what I am saying about decimal-point error applies to the case in the first post and I would not extend it further without checking.
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r.jhannsdttir, post #25: 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. Go to post
Decimal-point error has been discussed here with more heat than it deserves, mostly because two definitions have been in play the whole time.
n.torrence, post #35: Coming back to post #33, 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. Go to post
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.
For what it is worth, the same held on the two occasions I checked.
Collapsed as off-topic by two members at trust level 3 or above
Post #46 is the version of this I will quote in future. One addition.
I would rather this thread reach "we do not know" about decimal-point error than reach a confident answer that nobody can support when asked.
Where I part company with post #44, and it is a narrow parting.
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.
The claim is narrower than it sounds, and deliberately so.
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Two claims get bundled together under decimal-point error and they need separating. The descriptive one — this is what was observed — is usually well supported. The causal one — this is why — usually is not.
Almost every disagreement in threads like this one dissolves once you say which of the two you are making.
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isotonic_sheet, post #23: 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. Go to post
Post #48 describes the usual case. This is about the unusual one.
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.
Happy to be corrected if someone holds better data than mine.
A definition problem is doing most of the work in this decimal-point error discussion. Once the term is pinned down I suspect the disagreement mostly goes away and what is left is small.
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What I would check first on decimal-point error is whether the thing being measured moved or whether the way of measuring it moved. Those look identical in a graph.
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s.achebe, post #40: The arithmetic in post #37 is right; the assumption feeding it is the part to check. The failure mode on decimal-point error is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple to get wrong. Go to post
Post #51 and I disagree about the size of the effect, not about the direction.
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.
Second-hand, so weight it accordingly.
IHollingworth, post #29: 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. Go to post
Taking post #51 at face value and following it one step further.
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.
Scoping that to what I have actually seen rather than what I have read.
Decimal-point error was covered in the wiki last year and the page has a review date on it, which is a better starting point than my memory of a thread.
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Collapsed as off-topic by two members at trust level 3 or above
Good question, well framed, and I would like to see it answered properly.
Building on post #55 rather than restating it.
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 want a second opinion before relying on that.
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methods_margin, post #18: 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. Go to post
Whatever the answer on decimal-point error turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, invite the correction.