Very random question about needles

[tpad40]

Are the color-codes of needles universal? I.E. Is a red needle always 25G, Green 18G etc.? Even in human medicine?

I just got my first rabies shot (ow) and the nurse said she needed to get a bigger needle because she was not able to draw up the vaccine. She said she was going to "get a 21G or a 20G" and came back with a green hubbed needle...did I just get harpooned with an 18 guage needle?

Hmm...what color is a 21G anyways? Is it the ugly lime colored one?

Okay.../random

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[alliecat44]

Nope, not universal--they depend on the brand. Some overlap, but there are some differences in color.

21g is indeed a green color in some brands.

 

[DVMhopeful]

I wish the distbributers would get together and decide on a set of colors for each gauge, what a luxury that would be *sigh*

 

[ImaJerseyGirl]

..did I just get harpooned with an 18 guage needle?

Okay.../random

Ouch! I hope not! The brand I use at work does have green as the 18G. But you're right, you'd think the industry would standardize something as simple as color coding needle gauges!

 

[HopefulAg]

Just along the same lines because I was curious about the same thing, but the blood tube tops aren't universal either.

The system I'm used to is purple is EDTA, green is Lithium heparin, red is clot, and red/grey is separator. That system seems fairly universal in vet med, but when I had blood drawn they busted out a yellow top, which is evidently their clot tube. The rest were the same though (purple and green top).

Just an FYI in case someone was curious. The nurse looked at me like I was crazy when I asked lol, she had to go ask someone.

 

[david594]

Just along the same lines because I was curious about the same thing, but the blood tube tops aren't universal either.

The system I'm used to is purple is EDTA, green is Lithium heparin, red is clot, and red/grey is separator. That system seems fairly universal in vet med, but when I had blood drawn they busted out a yellow top, which is evidently their clot tube. The rest were the same though (purple and green top).

Fairly universal, except for the "Red tops". You get some that are "Serum" tubes which have a clot activator in them, while others are "no additive" tubes. And apparently if you put urine for a culture in a "Serum" Red top its the end of the world....(atleast per our local reference lab who has refused such samples)

 

[sumstorm]

Interesting. The needle the health department uses to reconstitute is HUGE and long...I swear I could give SQ fluids very quickly with it!

The nurse had problems getting it off of the syringe and said 'no way am I going to be able to inject you with this needle, like you would let me anyways!' but they did use a much smaller needle for the injection.

 

[DreamComeTrue09]

I just thought I'd add this....Very few are able to get blood from me! My veins are always visible EXCEPT when I go in to the doctors...I just know their going to take blood...and my veins suddenly disappear! Strangest thing...It's so annoying to because they'll pull the band around my arm tighter and tighter...and not a vein visible...it makes it even more stressful....even those that claim they can get blood from anything...have the hardest time getting blood from me!! One time they took it from my hand! Now that hurt.

 

[chris03333]

Just along the same lines because I was curious about the same thing, but the blood tube tops aren't universal either.

The system I'm used to is purple is EDTA, green is Lithium heparin, red is clot, and red/grey is separator. That system seems fairly universal in vet med, but when I had blood drawn they busted out a yellow top, which is evidently their clot tube. The rest were the same though (purple and green top).

Just an FYI in case someone was curious. The nurse looked at me like I was crazy when I asked lol, she had to go ask someone.

Yellow is a serum seperator (like our "tiger top" tubes). We have them in vet med also in yellow.

 

[david594]

Interesting. The needle the health department uses to reconstitute is HUGE and long...I swear I could give SQ fluids very quickly with it!

Some info from the Rabavert Dispensing instruction sheet:

Instructions for Reconstitutinq RabAvert using the longer of the 2 needles supplied, withdraw the entire contents of the Sterile Diluent for RabAvert into the syringe. Insert the needle at a 450 angle and slowly inject the entire contents of the diluent vial into the vaccine vial. Mix gently to avoid foaming. The white, freeze-dried vaccine dissolves to give a clear or slightly opaque suspension. Withdraw the total amount of dissolved vaccine into the syringe and replace the long needle with the smaller needle for injection. The reconstituted vaccine should be used immediately. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration. If either of these conditions exists, the vaccine should not be administered. A separate sterile syringe and needle or a sterile disposable unit should be used for each patient to prevent transmission of hepatitis and other infectious agents from person to person. Needles should not be recapped and should be properly disposed of.

How Supplied
Package with:
1 vial of freeze-dried vaccine containing a single dose
1 vial of Sterile Diluent for RabAvert (1 mL)
1 disposable syringe
1 smaller needle for injection, 25 gauge x l"
1 longer needle for reconstitution, 21 gauge x 1.5 "

So apparently the vaccine actually comes with its own syringe and needles. So the big scary needle might have just been a 21 gauge 1.5" needle.

 

[GeeQued]

All this needle talk is making me cringe, definitely going to put off my shots till I get yelled at. I get the lovely opportunity Wednesday to have a 4 inch 16 gage needle stuck into my stomach, I already fore-warned them they will be picking me up off the ground after I faint.

 

[twelvetigers]

Yellow is a serum seperator (like our "tiger top" tubes). We have them in vet med also in yellow.

I was going to say this, but she beat me to it!

There's a reason each color of tube is preferred for each test. Blue top tubes are great for D-DIMERs and coagulation profiles, but you'd never want to do a chemistry on the plasma from one of these because the sodium citrate (the anticoagulant) would falsely elevate the Na levels. I'm sure there are other reasons, but this is off the top of my head and I haven't worked at Antech for a year.

And apparently if you put urine for a culture in a "Serum" Red top its the end of the world....(atleast per our local reference lab who has refused such samples)

I think you should use a gray top tube for those. And keep it refrigerated! Reds are fine for regular urinalysis.

 

[david594]

I think you should use a gray top tube for those. And keep it refrigerated! Reds are fine for regular urinalysis.

Wow now! Refrigerated?!? We've been told not to refrigerate urine going out for a culture and that it should ideally be kept in an incubator?

All our urine goes out in red top "No additive" tubes. They are the most empty? tubes we have.

Off hand I know the BD Microtainer serum separator tubes are a yellow top.

 

[twelvetigers]

*shrug* The teaching hospital keeps all urine cultures in a refrigerator unless they're going straight over. What kind of clinic has an incubator sitting around? And why would you want the bacteria to start growing? I dunno. I just know what I've been told.

Yeah, who has gray top tubes on hand?

Grey-Top Tube (potassium oxalate/sodium fluoride): This tube contains potassium oxalate as an anticoagulant and sodium fluoride as a preservative – used to preserve glucose in whole blood and for some special chemistry tests.

These are just what the hospital always used. I'm actually not sure why.

there are also royal blue top tubes - those are used to identify specific, single elements - lead, nickel? Strange things. Poisonings maybe? We never saw many of those.

Did I tell you I once got a leg in a bag? It was a blue heeler leg. I had to feel it to see what it was. Oh, how I miss Antech.

 

[twelvetigers]

As an aside, if you choose to remember one thing from these boards in relation to your days on rotation at the hospital as a vet student and in your future years as a vet, remember this:

Blue-top tube (Sodium citrate): It is imperative that the collection tube is filled with stated volume of blood. Under-filled tubes will result in falsely prolonged values due to dilution of plasma with anticoagulant; and therefore cannot be processed. For example, 5.0 mL collection tube must have 4.5 mL of blood and 2.0 mL collection tube must have 1.8 mL of blood). The ratio of blood to anticoagulant is critical for valid coagulation test results.

A big issue! We always get this tiny amount. Fill the blue tops first!

And don't let your EDTA tubes clog - tilt those puppies back and forth from the instant they're drawn and don't stop until you put them in the lab technician's hands.

 

[LVT2DVM]

A big issue! We always get this tiny amount. Fill the blue tops first!

I hate to disagree with ya twelve tigers, but we were taught actually to ALWAYS prime the vacutainer with a serum separator first, because the epithelials present in the needles can effect the anticoagulant. So, we use a "dummy" RTT that draw about 1/2 ml into and just toss, then attach Citrate or EDTA next and then follow-up with our final SST/RT that gets submitted. But hey, whatever works right?

 

[twelvetigers]

That's right! That makes sense to me (a bit beyond my scope of knowledge, let's say) so I wouldn't be surprised if that's 100% exactly what needs to be done. I suppose I should just say that you can run a CBC and make a smear on a fairly small amount of blood (depending on the machine used) but you MUST HAVE about 2/3 of the tube full for any sort of coagulation profile (PT/PTT specifically). So make it a priority.

 

[david594]

But isnt LVT2DVM talking about doing a collection with an actual vacutainer collection system while TwelveTigers is talking about doing a syringe draw, and then filling tubes afterwards?

When doing a syringe draw wouldn't any epithelial cells be in all the blood, as opposed to just the first tube if using a vacutainer setup? Making it kind of a null point?

For good hematology practices don't you also want to make your slides ASAP to avoid RBC morphology changes due to the EDTA?

 

[twelvetigers]

Yes, I am indeed talking about a needle draw - sorry for confusion.

Well, considering that Antech gets thousands of LTTs a day for CBCs and smears and some of these may be nearly a day old... I think they are still viable, though they do tend to deteriorate through time. So <4 hours is ideal, but I think that the blood is viable just the same. Maybe in a perfect world... but we'd rather get a tube of slightly older blood than smears made by a tech or doc that... well... are less than perfect. To say the least.

I have seen some BAD blood smears. Lol.

 

[Mistoffeles]

so . . . when i pull a CBC, i always make slides to send with the LTT. am i risking ridicule every time i do this?

and, i've never been able to get a straight answer out of IDEXX on this. i've been told both that it's ok to use the butterfly cath to put the blood into the tubes, and i've been told that the preference is to use nothing less than a 21g needle. any thoughts from the lab professionals here? i'd love to be able to give my staff a directive straight from the source.

 

[twelvetigers]

I can't help you with the latter - no idea.

Slides are fine, but we usually would make our own anyway. We won't make fun if there's a smear with a nice, rounded feather edge that doesn't run off the end of the slide. The idea is to get the blood cells one layer thick on the very edge.

These are pretty good lookin':

 

[alliecat44]

Not a clinical pathologist, but we just had our final this morning...d'oh. Anyways...

My guess is that the comment about a 21ga needle being the smallest recommended is to reduce hemolysis (which can change certain chemistry values and CBC values if excessive). The smaller the needle, the more traume RBCs suffer when being pulled through it--both into the syringe and then shot out into the blood tube if doing a syringe draw.

Often, it is next to impossible to use something so large on our small animal patients, so we make do. The larger the needle we can get away with using, the better. Personally, I like to use 20ga needles on most cat necks, but some people think that's excessive. One way to minimize iatrogenic hemolysis if doing a syringe draw is to withdraw the needle from the patient, take off the needle, remove the stopper from the tube, and squirt it in that way. However, as twelvetigers pointed out, you have to be VERY sure you are putting in the correct amount for citrate (blue top) tubes. (I never do this for blue tops.) Another way to reduce hemolysis is to apply GENTLE suction on your syringe. These people who put like 2cc of suction on a 3ml syringe drive me nuts and are decreasing the value of their sample! The more suction=more trauma=more hemolysis=decreased accuracy of some chemistry results.

btw, it's also important for lavender tops to have at least the minimum recommended volume of blood in there. If there is too little blood to too much EDTA, it affects your CBC results. (If there's more blood than recommended, not a big deal.)

The changes seen with storage in EDTA are predictable and easy to spot/differentiate from pathologic change (i.e., due to illness), so refrigerating/storing samples in EDTA and sending them in isn't a big deal.