Originally Posted by
Far from massive
Thanks for your thread, I just learned something new if you are saying what I think you are. I always assumed you got a little less in you because of what is trapped in the needle, however,
On a 3ml BD syringe (And I would assume other brands) if you count down from the .5ml mark there are 6 lines, that is there is one line before the .1ml line. This is so that if you filled the syringe to .1ml then when you pushed the plunger in all the way it would actually give you .1ml (since the needle holds some fluid that will never be injected). So if you simply align the leading edge of the rubber tip with the amount you want to inject then you will inject that amount precisely. Conversly if you hold the syringe upward so that the air clears out the gear in the syringe, naturally this will not be as accurate a dose as if you use no air and go by the marks but you will save a little gear (of course if the air blows the gear back out the needle hole this will be negated) myself I don't push with air.
PS I just checked an insulin syringe and they are marked the same way.