LabKate said:Do it in two steps and it stops being confusing.
I am going to disagree with reconstituting low as a general rule. More diluent, more punctures, more in-use days at room temperature, and the stability trade-off is real. Precision is not the only variable being optimised.
The figures, for anyone assembling their own picture. Red flags, in rough order of how much they should worry you: no verifiable address, no batch numbers, prices far under market, vendor-commissioned tests only, pressure toward irreversible payment, and shipping with no temperature control.
Dr.NateNeph said:I am going to disagree with reconstituting low as a general rule.
There is a second half to this that has not been said yet. Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion. Synthesis, testing, and cold-chain shipping have floors. A price well under the floor means something was skipped, and the two things that get skipped are testing and content.
Worth separating that from vendor vetting, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.
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Shop Reference StandardsFollowing on from mia_MS2 — and this may be the naive question:
How to check the arithmetic without trusting a website calculator, since three calculators gave me three answers?
Closing the loop on my own question.
Resolved. I wrote mg, ml and mg/ml on the vial in marker and did the division in that order, and the two of us now get the same number every time.