5/18 Monoject vs Terumo Syringes

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Marje and Gracie

Marje and Gracie

Member Since 2010
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As many of you know, I have an ongoing "conversation" with Monoject regarding the inaccuracy of their syringes. The last two boxes that I received from ADW, the "stem" of the needle does not go down into the hub very far at all...you
can barely see it. More often than not, when I draw the dose, it results in a huge bubble along the side of the syringe that I can't get out no matter what I do including drawing alot of air into the syringe and then slowly expressing it.

I've been drawing insulin doses for 19 months and so I don't think there is a problem with my technique...it's just started being a problem with these latest syringes. And because I have to do so many redraws, I'm wasting insulin, too. grr_red grr_red grr_red grr_red So I called MJ again.....they sent me two new boxes of 31g syringes and a box of 30g syringes because Ella said she had an old box of 30g that seemed to be more accurate. Well...this box was not....still inaccurate. They also sent me a sharps shuttle and I sent them some samples of these 31g syringes with the short stem of the needle.

In my frustration, I ordered Terumos from ADW Terumo Syringes. I had ordered these last fall but found they are just as inaccurate as the MJs. However, now that I am using the calipers to measure doses, I don't have to worry about how accurate the markings are on the syringes. I use a "perfect" syringe to draw my dose, measure it with the caliper, and then always use that measurement for my dose and it seems to be working anti-jnix. I got the Terumos and MAN!!! They draw so nicely...it's amazing...no bubbles...nice and smooth..beautiful draw every single time.

My problem is, I have no idea how to translate the dose from the MJs to as close as possible on the Terumos. The Terumos barrel is more narrow. I tried to find a "perfect" syringe in both of them, draw up one unit, and then put it on a plate to see if they looked similar but they didn't. The MJ dose was more. Go figure.... I tried to weigh the doses as Diahann did when she did the syringe accuracy assessment but my scale, which does measure in tenths of grams, is not a Precision and so they barely registered. I'm still trying to work this from a scientific angle but if anyone has any ideas (Liz???), please let me know. I don't want to mess up how well Gracie is doing by making changes so if it comes down to it, I'll just keep using the MJs, wasting insulin, and not worry about it. But I'd LOVE to find a way to use these Terumos.

Also....for anyone who is doing larger dosing or their kitty is not so sensitive to small doses, I will be happy to send you the MJ 30g short needle (1/2 unit markings) syringes....brand new box. Please PM me.
 
I've actually been contemplating this for a while due to the number of frustrated microdosers here. Trying to count drops and weigh what comes out of the syringe - :o My thought is to measure the actual volume of the dose using a micropipettor. I was envisioning using the syringe to draw out a bit more than needed, squirting this out onto a clean surface (possibly a small square of teflon; not sure), using the micropipettor to pick up the exact volume desired, and then using a 2nd syringe for the injection. I'm not sure if (A) squirting out the dose from the micropipettor onto teflon or whatever and then sucking it into the 2nd syringe and then injecting, or (B) squirting the dose directly into the barrel of the 2nd syringe and then injecting would be better. I suspect that (B) would result in lots of extra air since the plunger is introduced after the insulin is in the barrel. But since you've got that caliper available, theoretically you'd only need to suck pre-measured doses back into the syringe and make note of the respective distances.

If there are 100 units of insulin per mL or 1000 uL, then there are 1 units in 10 uL or 0.1 units in 1 uL, etc. Tomorrow I need to come in to work, so I will bring a leftover U-100 syringe and play around with this. If it works like I think it will, I can loan you a micropipettor and send you some teflon.

Ideally they'd sell MORE DILUTE insulin so these microdoses wouldn't be an issue, but that's not gonna happen...

MJ
 
Marje, this may sound like a dumb question, but how are you detecting the difference in syringes? By eyeball?

On my pharmacy brand, it looks like the black surface of the plunger looks uneven when I turn it from side to side, but the whole box is like that. I can only try to be consistent from dose to dose. I can't possibly be exact with a dose that's not even on a line. (.75)

I asked DD what they use at the hospital for human patients, but they don't give micro doses, so the point is moot.

MJ's got a point. More dilute insulin would be so much easier.
 
Barb

If you mean the difference from one MJ syringe to the next.....yes, eyeball but I also have a 3x lighted magnifying glass. However, if you look at the zero line in relation to the plunger, you'll see the variation. If you mean between Terumos and Monojects, it's really easy to see the barrel of the Terumo is less in diameter with the naked eye.

MJ...that is extremely interesting and would probably be more accurate. One of the things I tried to do yesterday was to draw up my accurate dose with my calipers into the MJ syringe and then take the plunger out of the Terumo and squirt the insulin into the Terumo just so I could get a feel for how much it might be. But....you are exactly right....air, insulin settling or sticking to the side of the syringe, etc....it didn't work.
 
Yes Marje, I meant from one MJ to another. I need to examine mine again for the zero line. I had a problem with the plunger sliding down slightly, by itself today. I held the plunger tightly up, so it couldn't do that, as I poked the pen.

I also use a big lighted magnifier.
 
This discussion is fascinating, but I'm afraid that I'm not going to go to the lengths of weighing the insulin!! Or transferring insulin from one syringe to another. I have the calipers, but have been so busy I haven't had a chance to play with them yet. I have only rarely had the problem of the big air bubble down the side of the syringe. Usually I have been able to tap it up to the top and expel it. Occasionally I have just tossed that syringe. My old box of MJ 30-gauge syringes really is superior in every way to the MJ 31-gauge syringes I have been getting lately. It dates from last summer. The plunger is much thinner and lines up with the lines very well. The needle comes all the way down into the "cone". I'm saving them for when/if I ever need to microdose Rusty!!

Carry on, ladies!!

Ella
 
I hear you, Ella. Unfortunately, Gracie seems so sensitive to even drop changes. I wouldn't routinely draw up a dose in the MJ and then transfer it to the Terumo ;-) I was just trying to figure out if there was a way to determine the same dose as close as possible from MJs to Terumos. For now, I just will stick with the MJs so I don't disrupt her progress.
 
This is way beyond my area of expertise but I do wonder if there is a biology prof who might have some ideas. I'll ask around.
Liz
 
I had the same problem with the monojects. REALLY stubborn bubbles. I went back to the Relions. I've noticed the hub isn't always on straight. That got me wondering where I should measure with my calipers! Goodness sakes! I was measuring from the top of the hub to the insulin. Since I'm using .15, it's hard to measure from the bottom. But if the hub can be seated various amounts--that might change the dose also. But Simon seems to be steady on this method. Paws crossed. . .hopefully we can get this little project checked off soon and I won't need more syringes! But I might try Terumos if we do. ;-)
 
Since I'm doing this right now, I wanted to give an update.
I brought in a 0.3mL U-100 insulin syringe w/half units and short needle and drew up what to my eye is 1 unit. I squirted it out and used a micropipettor to determine the volume. It should be 10 uL, but it was 14 uL. I tried 0.5U as well, which should be 5 uL, and it was 9 uL.

So, YUCK! Completely unacceptable :?

Initially I tried placing a 10 uL drop on a piece of teflon and then drawing it into the insulin syringe, but the beveled needle made it difficult to suck up the last miniscule molecules. This may just take practice though, and is probably sufficiently reproducible for dosage purposes. I found it works much better if the needle is more sideways than vertical so the beveled edge can draw up the liquid droplet.

It looks like Gracie is currently at ~0.75U. Let me know so I can send you the appropriate micropipettor, assuming you want to try to tackle this with your syringes. I think one that can measure ranges from 0.5-20 uL will be sufficient. The little pieces of teflon worked well to keep the liquid beaded up (I just used water). I can also send you a fixed-volume 10 uL pipettor to keep. Theoretically, if you use your calipers to determine the syringe distance for 1U (=10 uL), you can calculate the distance for any fractional doses from that, assuming the barrel is a perfect cylinder. If, for example, you draw up to a specific distance on the barrel, squirt it out and measure the volume, you'll have: "distance X = uL Y" like "2 mm = 10 uL(=1U)"; so if you want 0.75U, it would be 7.5 uL or 1.5 mm on the calipers.

Check this over and make sure my logic is correct :roll:

MJ
 
MJ

I do really appreciate the offer but I think I've already got it worked out that way altho the exact amount in 1u seems to be questionable, eh? What I did was get a MJ syringe that looked about as perfect as it can. I drew up 1u and measured it with my calipers like you said. Then I took off one of my drops to the next dose....it was .07mm less than the 1u; and I continued to do the same thing for several lesser doses. So I figure each drop measures .07mm less. For example, 1u is 1.43mm; a sk1u is 1.37mm; a f.75 is 1.3mm; a c.75 is 1.23mm.

I don't even use the markings anymore. I just use my calipers and measure the dose as consistently as I can. So I think I'll just do that and forget about the Terumos. I experimented with the Terumos today for quite some time and one reason I have decided to not use them is they glide a little "too" smoothly. It's hard to microdose with them. If you barely touch the plunger, it eeks off two drops before you know it. They are probably awesome for high dosers but not for microdosing.

Thank you for going to all this trouble AND it is excellent information to have.
 
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