? Syringe plunger question

[squeem3]

Starting a new thread to ask a question about this post about the syringe plunger @Brianna & Xander posted about because now I'm confused : https://www.felinediabetes.com/FDMB/threads/where-do-people-buy-their-lantus-from.299677/

Do you push the plunger all the way to the end before drawing up insulin? Or do you push the plunger just to the zero line and then draw up insulin?

I was looking at my BD syringes this morning and if I push the plunger to the zero line, there's a little bit of airspace between the plunger and the needle. Is that air space ok and I still get the correct amount of insulin after I tap out the air?

I normally just push the plunger all the way down so it's flush against the needle and then draw up insulin. According to what Brianna posted, once the plunger is pulled past zero there will be insulin in the syringe and that tiny amount means your actual insulin dose is a teeny bit more than you think.

 

[Helen + Noogi]

That's such an interesting question!
I use BD syringes too and do so the same as you - plunger all the way down, then draw.

I don't use calipers but I do cross check against this insulin ruler (specifically for BD syringes): https://www.diabetes-katzen.net/insulinruler.pdf
Haven't cut out the measuring strips, but just lay the page flat and put my pulled syringe on top and look carefully from above with a bright light to check it's correct.

I spent quite some time stressing about whether I should be reading from the top edge or bottom edge or middle of the top plunger rubber. The insulin ruler says it needs to be the middle, which I find very difficult. So I measure from the top of the top plunger rubber. And it still matches up to the ruler measurements on the sheet. Fortunately for me I haven't had issues with the markings on BD syringes being inconsistent.

When I read up about this initially I remember someone saying that it doesn't actually matter too much which way of measuring you choose, as long as you are consistent. If kitty is consistently getting a smidge more than the actual correct amount is not such a big deal, as long as it is exactly the same every day.

I guess this does become more of an issue should you get to the tiny measurements: 0.5, 0.25, 0.1 and a drop. I'm not there (yet).

 

[squeem3]

I've been using syringes for years at work and that's how I was taught to measure: push plunger to the end past the zero line to minimize dead space, then draw up the liquid. The top of the plunger, the end touching the liquid, lines up with the syringe marking.

When I read up about this initially I remember someone saying that it doesn't actually matter too much which way of measuring you choose, as long as you are consistent. If kitty is consistently getting a smidge more than the actual correct amount is not such a big deal, as long as it is exactly the same every day.

Good point.

 

[Wendy&Neko]

I ended up using calipers with my BD syringes. I swear some of them had up to 1/3 of a unit under the zero line. Her final dose was under the zero line. . I pushed the plunger down on each syringe, and measured from there.

 

[Brianna & Xander]

Yeah, the plunger being up above the 0 line was when it was pushed all the way in. Like Wendy said, some of them are like a full third of a unit beyond that which is crazy.

It's very possible that I'm wrong and it doesn't matter (I don't want to be spreading misinformation), but what made sense to me is that I have to start measuring from where the insulin starts. If there's already insulin in the syringe above the 0, then the 0 is wrong and I have to adjust for it.

When I read up about this initially I remember someone saying that it doesn't actually matter too much which way of measuring you choose, as long as you are consistent. If kitty is consistently getting a smidge more than the actual correct amount is not such a big deal, as long as it is exactly the same every day.

This is basically the conclusion I came to as well. It's so difficult for me to move the plungers on that minute a level. I just try to be consistent about it... As much as I can with the ever-changing syringes, anyway. I really should just get some calipers. Funds are just tight and it's hard to constantly buying new things to try.

 

[squeem3]

Top of the plunger touching the zero line:

The zero line is in the middle of the plunger:

Plunger pushed all the way to the end, past the zero line. Notice the teeny bit of airspace above the plunger. Problem or not? I typically push the plunger firmly against the bottom of the syringe and hold it there while I poke the needle into the pen and slowly draw out the insulin.

 

[Brianna & Xander]

Problem or not?

I don't know the answer, but I'm curious too. Like I said, I could very well be wrong. I would just rather have accidentally undershot than overshot, so I did what made sense to me. I'm sorry if I've caused a lot of confusion/chaos over nothing.