Practice · Reconstitution · continued

Follow-up: The decimal-point error, and the habit that catches it posts 121–132

Practice › Reconstitution concentration maths bacteriostatic water dead volume reconstitution Closed

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

dr_seongTL3Physician16 Dec 2025#121

l.diallo, post #4: 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. Go to post

Practical note on decimal-point error: write down what you expect before you look. The number of times I have found what I went looking for is higher than chance would allow.

6 likes in reply to #4 7mo

i.almeidaTL218 Dec 2025#122

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.

That is one dataset and I would not build a rule on it.

1 like 7mo

customs_ledgerTL3Regular19 Dec 2025 · edited#123

Where I part company with post #121, 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 answer changed when I changed how I was measuring, which was informative.

0 likes 7mo

c.vasquezTL221 Dec 2025#124

Post #121 is the version of this I will quote in future. One addition.

Decimal-point error is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says which one is being asked for.

22 likes 7mo

w.novakTL3Regular22 Dec 2025#125

s.chowdhury, post #17: 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. Go to post

Answering the question post #121 raises rather than the one it answers.

For anyone finding this later: the short answer on decimal-point error is that it depends on one thing, and the rest of the thread is people identifying which thing.

3 likes in reply to #17 7mo

p.ostergaardTL223 Dec 2025#126

n.nakamura, post #114: 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. Go to post

Understood, and I withdraw the assumption I opened with.

0 likes in reply to #114 7mo

c.okaforTL325 Dec 2025#127

Collapsed as off-topic by two members at trust level 3 or above

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.

n.kravchenkoTL226 Dec 2025#128

Building on post #125 rather than restating it.

16 likes 7mo

crossref_checkTL3Wiki editor28 Dec 2025#129

Before the thread moves on from decimal-point error — what is the sample size behind the claim? I am not being difficult; I have seen the same figure quoted from an n of four and from an n of four hundred.

15 likes 7mo

k.asanteTL229 Dec 2025#130

This follows post #129 rather than contradicting it.

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.

That has held every time I have looked, which is not the same as always.

6 likes 7mo

ne.laurentTL230 Dec 2025#131

One more thing on decimal-point error that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent contradiction disappears.

0 likes 7mo

n.bridgewaterTL2Member1 Jan 2026#132

i.beaulieu, post #50: 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. Go to post

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.

0 likes in reply to #50 7mo

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Coming back to: Swirling versus inverting versus leaving it alonePractice › Reconstitution · 24 replies

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