help me understand insulin syringe, I have read the wiki twice
Asking properly rather than in a comment on somebody else’s thread: help me understand insulin syringe, I have read the wiki twice.
Shook the first vial because nobody told me not to. It was fine, but I have swirled every one since.
Wrote the date on the vial as well as the concentration after losing track of which one was opened first.
Started reconstituting everything to a round concentration and the six-in-the-morning error rate went to zero.
Corrections welcome, especially the pedantic ones. Pedantry is how this board earns its reputation.
best — the order this archive was captured in
Bacteriostatic water contains benzyl alcohol as a preservative, which is what makes repeated entry into the same vial reasonable. Plain sterile water has no preservative.
Working has to be shown on arithmetic posts. Added a note asking for it rather than removing this one.
Working has to be shown on arithmetic posts.
Right, and the arithmetic behind it: 15mg in 3mL is 5mg/mL, so 0.75mg is 15 units.
Small fix — a U-100 syringe is 100 units per mL. If yours is marked differently it is not U-100 and the whole calculation changes.
Why "more water" keeps confusing people, including me for a month.
The vial contains a fixed amount of peptide. Water changes nothing about that amount. What it changes is concentration, and concentration is the divisor between the dose you want and the volume you draw.
So doubling the water halves the concentration and doubles the units for the same dose. Nothing is diluted in any sense that matters; you are simply reading a bigger number off the same barrel. Pick the water volume that puts your usual dose on a whole number of units and life gets easier.
20mg into 2mL is 10mg/mL, and 0.5mg of that is 5 units
20mg into 2mL is 10mg/mL, and 0.5mg of that is 5 units
Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.
aim the stream at the glass wall, not at the cake
the number you write down is the number you will trust at 6am
Right — the volume you add is the only variable you control here, and the cake does not change it meaningfully.
I keep a laminated card in the drawer with the arithmetic on it. Looks ridiculous. Has never once let me draw the wrong volume.
This. Showing the working is the fastest way for somebody else to spot the mistake.
Same. I got this wrong once, caught it because the units looked absurd, and have written on every vial since.
dead space in the needle hub is real and it is small
I would not round that figure. At 10mg/mL a rounding error of two units is a real fraction of the intended amount.
- 1Bacteriostatic water contains benzyl alcohol as a preservative, which is…8 comments in this branch · started by u/marta_weiss
- 2Right — the volume you add is the only variable you control here, and the…6 comments in this branch · started by u/RetaAndRegret2