Pens and their accuracy in dosage

[Simone Thompson]

Hiya, Had various pens for years now and I recall a Nurse Specialist telling me to 'check' the pen is dosing accurately, dial up 20 units and inject into the empty BD needle case (I use BD Micro-Fine+ 0.25x8mm needles) the 20 units should come up level with the straight area where the needle was located before it bows out- the length of the needle here is very important as this straight area would be shorter or longer Don't know if this applies to other disposable needle cases? Can anyone else confirm the above still carries or if not have they any other 'schemes' they know of to ensure when I inject 10 units I am getting ten units as sometimes I am not quite so sure - resistance, small bubbles that squeeze up when injecting but that are so small I can't shoot 'em out, injection site. Any ideas would be helpful ....

 

[Robin]

the length of the needle here is very important as this straight area would be shorter or longer

Hi Simone, this isn't something I've ever been told to check, but I remember reading somewhere that you could measure your insulin dose in this way, but that the needle length didn't matter, as all the cases were the same length. I've just checked this out, looking at an old BD microfine 8mm one I've got hanging around, and a BD microfine 4mm from the ones I currently use, and they are indeed the same size. The needle just doesn't come so far down the casing with the shorter ones. (Next experiment will be to check the needle case size with the new brand I've just had prescribed, to see if it's the same)

 

[Matt Cycle]

Hi Simone. I've never checked it either. Have you got any old disposable syringes lying around? (I've still got a few as part of my diabetes bits and pieces collection). If so you could pull the plunger out and fire it in and check your pen dosage against that. Should be a bit easier to check.

 

[Robin]

Just experimented. 20 units does indeed fill the straight bit on a BD microfine case, but my new brand (Nipro Sure) has a completely different shaped cap, and a 20unit shot fills it to a random point in the curved bit.
( before anyone accuses me of wasting precious insulin, I did this with the tail end of a Levemir cartridge I was about to chuck because a) it's been out of the fridge more than 28days, and b) travelled abroad and back in dubious high temperatures)
Nipro needle case is on the left, I think you can just see the 'fill' line. You can't see the fill line in the microfine, because it's exactly at the top of the straight bit.
( I need to get a life, I Should be doing my holiday ironing. Anything for a displacement activity!)

 

[Simone Thompson]

Wow Robin, a sleuth and IT expert in one ... attaching photo's I am very impressed - ah clever BD using same cases, just this is all I have ever heard from the Nurse years ago - can't find anything on t'internet as not quite sure what to type have tried but just get medical scientific research results on variances in pen doses ... very confusing - just wanted it verified really. What you said made me think these cases may have changed over the years - I think I will contact BD to see if they can throw any light on my question - let me know if new case is any different. I will post back later with my replay from BD ...

 

[Simone Thompson]

Hi Simone. I've never checked it either. Have you got any old disposable syringes lying around? (I've still got a few as part of my diabetes bits and pieces collection). If so you could pull the plunger out and fire it in and check your pen dosage against that. Should be a bit easier to check.

Clever never thought of that one I'll have dig around ....

 

[Simone Thompson]

Just experimented. 20 units does indeed fill the straight bit on a BD microfine case, but my new brand (Nipro Sure) has a completely different shaped cap, and a 20unit shot fills it to a random point in the curved bit.
( before anyone accuses me of wasting precious insulin, I did this with the tail end of a Levemir cartridge I was about to chuck because a) it's been out of the fridge more than 28days, and b) travelled abroad and back in dubious high temperatures)
Nipro needle case is on the left, I think you can just see the 'fill' line. You can't see the fill line in the microfine, because it's exactly at the top of the straight bit.
( I need to get a life, I Should be doing my holiday ironing. Anything for a displacement activity!)
View attachment 9783

I love your (ahem - excuses for the insulin use - I have often queried me throwing away a vile that has been hanging around in spare pen you feel somewhat criminal and need to do this surreptitiously under cover of darkness). Holiday ironing should use up a number of carbs so I mustn't stop you - think of the beneficial exercise and b/s lowering activity....yawn,yawn haha