U-40 Versus U-100 Insulin Syringes and Pens
I recently got a letter asking me to help choose the best insulin syringe for a pet. So today I’ll first explain the goofy lingo we use to describe insulin syringes and then discuss needles and pens and syringe volume. It’s really quite simple once you break it down. Some of it is critical to proper dosing and some of it is merely personal preference.
What is the Difference Between U-40 and U-100?
U-40 means there are 40 units of insulin per cc. U-100 means there are 100 units of insulin per cc. It refers to concentration of insulin. Remember that one cc (cubic centimeter) equals one ml (milliliter). This is an important aspect of choosing a syringe. If your vet chose U-40 insulin for your pet, you need a U-40 syringe. If you use U-100 insulin you should choose a U-100 syringe. There are conversion tables on the Internet to use one type of syringe with the other type of insulin, but it gets too confusing. I advise against such a mismatch. Mistakes can be made. Dosing errors can be costly or even deadly. Just choose the right syringe for the insulin your vet chooses for your pet.
Regardless of this, syringes can be of different volume. Veterinarians often choose 1/3cc or 1/2cc syringes for our patients as these smaller volume syringes make it much easier for us to see the markings for pets. Pets are usually much smaller than the average human! Sometimes (rarely) we might use 1cc syringes for really big dogs. Let’s use an example: Say you have U-100 insulin and have a really big dog taking 32 units of insulin. A 3/10cc syringe would only allow up to 30 units of U-100 in Continue reading