Insulin

christina731 · Jul 7, 2014

Could someone please help me understand what the U in U100 insulin stands for? On a website I found it states that U100 means that there are 100 units of insulin per mL of liquid. Would that mean that a U40 syringe only has 40 units of insulin per mL and if that is the case how would you know what syringe to use when looking at a Dr.'s prescription?
Any feedback would be greatly appreciated. =)

The U stands for units and you're correct about U100 = 100 units per mL. It doesn't matter what syringe you use as long as it's capable of holding the quantity of insulin ordered. For example if the order is for 25 units and the syringe can hold 30, then that will work. But if the order is for 40 units and you only have a 30 unit syringe you cannot give it in one dose. I've never heard of a U40 syringe (a quick google search returns animal/veterinary uses but not human) unless it's something pre-made by pharmacy as a syringe containing 40 units of insulin. Most syringes come in 30, 50, and 100 unit capacities. I suppose if one were using said U40 syringe you can potentially draw up to 40 units into it but it would be from a vial, not pre-packaged with 40 units. Someone please correct me if I'm wrong. I do not work in endocrinology but I have experience with insulin.

mrsboots87 · Jul 7, 2014

The type of syringe will not change the amount of insulin per mL in the vial. No matter what, the concentration in a vial of untampered with U100 insulin will be 100 units per mL. A 40 unit syringe means just that. That the syrynge itself can hold up to 40 units of U100 insulin. Because of the way insulin is dosed, only ever use a syringe that matches the unit concentration of the prescription. If prescribed U100 insulin, then use syringe specifically made for U100 insulin. For U500 insulin, use only U500 syringes. There will never be a "U40" insulin syringe. There are U100 and U500 then they will have different unit max. As in they can hold up to 10, 30, 50, 100, whatever units in the syringe.

If you are asking for personal insulin use, i would highly suggest sitting down with your prescribing physician and have them explain this to you in person so they can show you haw to tell the difference between the syringes and how to properly measure your prescribed dose.

purple12 · Jul 9, 2014

Thank-you for your responses. This really helped to clear things up for me. I'm a 1st year nursing student. I asked my teacher to explain this to me and I just couldn't wrap my brain around her explanation. :)

amoLucia · Jul 9, 2014

HELP!

I'm having to dust the cobwebs out of my brain, but way, way, waaaay back in the stone age, I think I do remember insulins used to come in U40 and U80 strengths and there WERE U40 and U80 syringes. One cc of U40 contained 40 units of insulin while U80 contained 80 units per cc. One always had to be careful that the right strength insulin was drawn up with the correct calibrated syringe. Were many, many errors made and that's why the industry switched over to standardizing insulins to U100 and U100 syringes. That was such a relief! I don't think they made any of the old strengths /old syringes anymore.

I could be wrong about this as this was way back when I was still a student, so I ask for some verification from some of the more senior experienced nurses out there.

And I also remember insulins being made of pork or beef derivatives, not synthetic, like today. Again, you had to be very aware of pork insulin as it could NOT be used with some Jewish or Muslim pts. And there were some pts who just had plain out old fashioned allergies to pork (beef seemed to be better tolerated).