Dead space refers to the amount of fluid that is wasted when performing an injection. This is fluid that is trapped in the syringe or in the needle. With a standard Luer lock needle/syringe this can be up to 0.1mL, whereas in an insulin needle can be as low as 0.003mL. Reducing dead space is recommended for economic reasons because it adds up to a lot of wasted estrogen. This calculator can be useful for estimating how much estrogen is wasted depending on the supplies used.
One thing to note if you are swapping needles for drawing and injecting, then you should pull the plunger back slightly prior to taking off the drawing needle so that the fluid inside the drawing needle is not wasted. It is very minor, but it can make a difference. See Question 7.7 for another possible strategy if concerned about high dead space.
+One thing to note if you are swapping needles for drawing and injecting, then you should pull the plunger back slightly prior to taking off the drawing needle so that the fluid inside the drawing needle is not wasted. It is very minor, but it can make a difference. Note as well that syringe markings already account for dead space, so you should not manually add more to your injection. See Question 7.7 for another possible strategy if concerned about high dead space.
Source code available here on GitHub.
Full Compilation Datetime: Tue Oct 21 13:10:20 2025
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(There aren’t LaTeXML bindings for datetime2, hanging, or hyphenat, so the formatting is slightly ugly. If you’d really like to help me out, please write those bindings!!!)
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