Syringe Conversion

[scienceofcats]

Hey guys, so I’m a complete idiot and I forgot to get more U40 syringes. My vet is not open until tomorrow, so I bought U100 syringes at the pharmacy to use one time only until I can get more of the regular ones.

I’m probably paranoid, but can you guys confirm that I’ve done my conversions right? Lola’s dose is currently 1.25 units of ProZinc U40 insulin, which according to this chart would mean I would draw up the insulin to the 3.1 unit mark on a U100 syringe. That’s right, right?

 

[Bear & Lora]

So I have recently converted from U-40 to U-100 also using Prozinc. (1.2 U-40 converts to 3 on U-100). The next dose for U-40 on the conversion chart is 1.4 which is more than 1.25.
There isn't a 3.1 Unit marking on the U-100.
The lines with the numbers are full units the lines to the left are half units.
If you are looking at the conversion chart you will notice the U-100 numbers go full unit then full unit and a half, example 3 Unit, 3.5 Unit, 4 Unit, 4.5 Unit.

 

[scienceofcats]

Right, sorry for not being clear - I realize there isn’t a 3.1 unit mark, but that this would just be a hair past 3. But to be safe, I’ll just draw up to the 3-unit line, which means 1.2 units of insulin, which is close enough to her normal dose.

 

[Elizabeth and Bertie]

Lola’s dose is currently 1.25 units of ProZinc U40 insulin, which according to this chart would mean I would draw up the insulin to the 3.1 unit mark on a U100 syringe. That’s right, right?

Correct.
The 'multiplier' is 2.5.
That's because U100 insulin is 2.5 times 'stronger' (2.5 times the number of insulin units per ml) than U40 insulin which has 40 units per ml.
So, for one unit of U40 insulin you measure to the 2.5 mark on a U100 syringe, etc, etc... And yes, for some doses it does mean that you'll be measuring between the lines.
There's an FDMB version of the conversion chart here: http://www.felinediabetes.com/insulin-conversions.htm

The whole 'conversion chart' thingy can be difficult to get your head around at first. And of course we want to make sure we're measuring the right dose for our cat!
If you still have a U40 syringe around, even a used one, you can draw up some coloured liquid into it (cold tea will do) to the one unit mark, and then draw up to the 2.5 unit mark in the U100 syringe. If you then squirt those out onto kitchen paper you should be able to see that they are the same amount.

Eliz