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Practice · Reconstitution · continued

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.

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VPoulsenTL314 Dec 2025#31
IW
i.wojcikTL215 Dec 2025#32
baseline_table, post #12: What I can speak to on decimal-point error is narrow, so I will keep it narrow rather than generalising from it. Beyond that boundary I do not know. Go to post

Two questions I would want answered before drawing anything from the decimal-point error data above: how were the cases selected, and what happened to the ones that dropped out.

18 likes in reply to #12 7mo
CC
crossref_checkTL3Wiki editor15 Dec 2025#33

Reading rather than contributing, but this is the most useful thread I have found on it.

0 likes 7mo
ND
n.duarteTL215 Dec 2025#34

I had written a reply contradicting post #30 and deleted it. Here is what survived.

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.

0 likes 7mo
TK
t.kulkarniTL3Regular15 Dec 2025 · edited#35

Picking up post #32: that is the part I would want checked first.

I would keep decimal-point error and the decision it usually gets used for separate in this thread. They are related and they are not the same question, and merging them is why the last one went badly.

12 likes 7mo
GO
g.oyelaranTL215 Dec 2025#36

Decimal-point error looks different depending on whether you are reading the primary literature or the summaries of it, and the difference is not in our favour.

25 likes 7mo
BE
bench_entryTL3Regular15 Dec 2025#37
am.wikstrom, post #22: 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

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.

Anyone with a larger sample, please post it.

0 likes in reply to #22 7mo
BF
b.friskTL215 Dec 2025#38

The practical version of decimal-point error is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached.

1 like 7mo
VT
vial_tableTL2Member15 Dec 2025#39
g.oyelaran, post #36: Decimal-point error looks different depending on whether you are reading the primary literature or the summaries of it, and the difference is not in our favour. Go to post

Narrowing post #36, because the general version has more than one 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.

Not a strong opinion, just a consistent one.

2 likes in reply to #36 7mo
DV
d.vestergaardTL215 Dec 2025#40
owen.brady, post #7: I read post #5 twice before replying, because I had assumed the opposite. 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

Saving this. It is the version I will quote when the question comes round again.

8 likes in reply to #7 7mo
ID
i.dumitruTL215 Dec 2025#41

Answering the question post #39 raises rather than the one it answers.

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 have deliberately not rounded that, because the rounding is where the argument starts.

2 likes 7mo
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RidgewayTL3Regular15 Dec 2025#42
n.duarte, post #34: I had written a reply contradicting post #30 and deleted it. Here is what survived. 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. Go to post

What I would tell a new member reading about decimal-point error for the first time: the confident posts are not the reliable ones, and the reliable ones are longer.

0 likes in reply to #34 7mo
IG
i.grimaldiTL215 Dec 2025#43

The strongest argument against my own position on decimal-point error, stated as well as I can state it, since nobody else has yet.

22 likes 7mo
EF
erratum_fileTL3Regular15 Dec 2025 · edited#44

Post #43 is the version of this I will quote in future. One addition.

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.

10 likes 7mo
CV
ca.vermeulenTL215 Dec 2025#45

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.

5 likes 7mo
HN
h.nicolaidesTL3Regular15 Dec 2025#46

Where the decimal-point error reasoning breaks down for me is the step from the group result to the individual case. That step is almost never argued for.

0 likes 7mo
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in.guerreroTL215 Dec 2025#47

Noted, and thank you for writing it out rather than summarising it.

29 likes 7mo
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endpoint_lineTL3Regular15 Dec 2025#48

Building on post #46 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.

A qualification I should have led with rather than closed on.

15 likes 7mo
MD
m.dumitruTL215 Dec 2025#49

An honest declaration on decimal-point error: I have a prior here and it is strong enough that you should weight what I say downward. Stating it rather than hiding it.

0 likes 7mo
DW
diluent_watchTL2Member15 Dec 2025#50
VPoulsen, post #31: Careful with the language on decimal-point error. "Not detected" and "not present" are different findings and the first is a statement about the method. Go to post

Post #48 answers the question as asked. The question underneath it is different.

Having read the whole decimal-point error thread before replying: the question in the first post has not actually been answered yet, and three of us have answered a nearby one instead.

30 likes in reply to #31 7mo
HF
h.falkTL215 Dec 2025#51

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.

The general answer and the answer for your case may diverge here.

6 likes 7mo
TD
titration_diaryTL3Regular16 Dec 2025#52
mira.patel, post #5: The confident answers on decimal-point error and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category. Go to post

Everything in post #48 holds. The case it does not cover is the one I have.

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.

I have no interest in any supplier named above.

16 likes in reply to #5 7mo
IG
i.guerreroTL216 Dec 2025#53
taper_file, post #16: Decimal-point error is a question about a distribution, not about a value, and treating it as a value is what produces the confident wrong answers. Go to post

On decimal-point error: the maintained page in the documentation commons covers the general case with citations and a review date, which is more reliable than any reply here including this one.

0 likes in reply to #16 7mo
BW
bac_waterTL2Regular16 Dec 2025#54

Answering the decimal-point error question as asked, then the question I think is meant. As asked: yes, with the qualification below. As meant: it depends on how the first measurement was taken.

1 like 7mo
SZ
s.zamoraTL216 Dec 2025#55

The arithmetic in post #54 is right; the assumption feeding it is the part to check.

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 have said this before in a thread nobody could find, so it is worth repeating.

3 likes 7mo
DS
d.szymanskiTL3Wiki editor16 Dec 2025 · edited#56

Understood. Thank you for being specific about the limits of it.

11 likes 7mo
JR
j.restrepoTL216 Dec 2025#57
b.brandt, post #24: Post #21 is right about the mechanism and I think understates the practical bit. 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 would not lead a decision with this, but I would not ignore it either. Go to post

What I would want before treating decimal-point error as settled: the method, the sample, and whether anyone tried to find the opposite result. Two of the three are usually missing.

31 likes in reply to #24 7mo
K
KAnderssonTL3Regular16 Dec 2025#58

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.

The uncertainty is in the assumption, not in the calculation.

0 likes 7mo
EF
e.ferreiraTL3Regular16 Dec 2025#59
b.frisk, post #38: The practical version of decimal-point error is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached. Go to post

I keep a log for decimal-point error specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost nothing and settled it.

1 like in reply to #38 7mo
CW
c.wijnbergTL2Member16 Dec 2025#60
titration_diary, post #52: Everything in post #48 holds. The case it does not cover is the one I have. 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. I have no interest in any supplier named above. Go to post

Two things can be true about decimal-point error at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people defending the first against attacks on the second.

6 likes in reply to #52 7mo