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c/reconstitution·submitted 26 days ago by u/quarter_dose_queen

[Question] how do you actually verify concentration

Questionbranch of 6 comments

The title is the whole question — how do you actually verify concentration — but here is why I am asking. Started reconstituting everything to a round concentration and the six-in-the-morning error rate went to zero. The dead space question sent me down a rabbit hole for a week. It is a fraction of a unit and it is…

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6 comments, started 26 days ago
u/rasmus_kuipers70 points·26 days ago

This. Showing the working is the fastest way for somebody else to spot the mistake.

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u/ines_lindqvist33 points·25 days ago

Disagree with the "more water is safer" framing. It is not safer, it is just a different number to divide by.

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u/quarter_dose_queenOPlow and slow19 points·25 days ago·edited

How many mg in the vial and how many mL are you adding?

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u/ledger_modmod · vetting82 points·25 days ago

Careful — that arithmetic is wrong. 30mg in 3mL is 10mg/mL, so 2mg draws to 20 units, not what you wrote.

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u/karl_fischer_kev66 points·25 days ago

twice as much water halves the concentration and doubles the units for the same dose

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u/sock_puppet_spotter29 points·25 days ago

Reconstituted at 2mL when I meant to use a different volume. Caught it because the units looked wrong on the barrel. Now I write 10mg/mL on the glass before I put the cap back.

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About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

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