CBC clotting

soprano3 · Apr 12, 2010

:nurse:Yes, and not all heelsticks, sometimes venous or art sticks. I think it's the amount of heparin they put in the container, maybe it dries out after a while. If we draw the blood & quickly walk it down to the lab shaking it constantly, it helps.

We have been having many CBC specimens clot! We are tracking the number clotted and are coming up with about 7-9%! These are all specimens obtained by heelstick. Anyone else have this problem in their unit???

RN4Little1s · Apr 16, 2010

We are having a huge problem with this! We are supposed to write a safety report every time it happens... we can't be drawing CBCs one after another on these tiny babies, depleting their body! As the ones drawing labs, we felt we were doing everything in power to keep it from clotting. We would shake it all the way to the lab and produce to them a runny specimen void of clots... only to get a call an hour later that it clotted and we would have to draw it again if "we really wanted it." Yes, we really want it. But after a 3rd stick, many times the pracitioner would just give up ordering it and get one later, possibly delaying necessary treatment and changing the outcome negatively. It was happening with a-line specimens with us too!

The only thing we could do was hand deliver the specimen to the lab, ask to speak with somebody who could run it, explain this was a 1 kg baby who didn't have blood to get them a 2nd time, and make them run the sample in front of us.

The lab people produced a powerpoint for us on "how to draw labs" which of course was how we were doing it already... Next, the lab sort of admitted it was a processing problem. (We had suspected that they were leaving the specimens too long even when they were labeled STAT. Lab told us that if the specimen sat there for days they would still be able to run it if had arrived to them clot-free. Ha.) They got a new barcode system that made their processing faster and better. The incidence of clotting has gone down now... hopefully it keeps getting better!

SteveNNP, MSN, NP · Apr 18, 2010

1. People put too much blood in the microtainers, depleting all the anticoagulant in the tube. All you need is 300 microliters, between the 1st and second line.

2. Shaking. Lyses RBCs, causing clotting cascade activation.

3. Scraping the heel while obtaining sample: RBC lysis, clotting cascade activation.

So, it's not always the lab's fault, though it is most of the time!

I'mANurse! · Apr 19, 2010

I agree with SteveNNP, only fill the tube halfway between the first and second lines. My CBCs used to always clot when I first started working in the NICU, until a coworker shared this tip with me. They rarely clot now, unless the kid has really sludgy blood!

dawnebeth · Apr 20, 2010

We don't do CBCs by heelstick--ever. In our nursery, we always do a venapuncture, or arterial stick. Although we have them clot once in a while--and sometimes I do suspect that the lab is holding the specimen too long--I agree with what others have said. Fill the small tube only halfway through and only shake right at the beginning, just once or twice.

SteveNNP, MSN, NP · Apr 20, 2010

I've found that by rolling the tube gently between your hands helps get all the anticoagulant off the tube walls, and keeps CBCs from clotting. My first night in NICU, I had all 4 CBCs clot on me...twice. Now, they rarely do if I stick to proper technique like I mentioned above.

We only do art sticks here for blood cultures and large-volume labs like karyotype/FISH.

Mimi2RN, ASN, RN · Apr 21, 2010

We used to fill between the two lines, but according to the lab, they now have new equipment and the tubes have to be filled to the top line. We always hand carry our lab specimens to the lab, we used to use the tube system, but the specimens would get lost.

We still have phone calls that the blood clotted. One problem is the length of time the blood sits in the lab, when the phone call comes an hour later, we know it's been too long!

Love_2_Learn · Apr 21, 2010

Sending a big Thank You to Steve for his perfectly logical explanation about the lysing of the RBCs causing the clotting cascade to begin.

I remember learning to gently turn the tube back and forth about 5 to 8 times after placing the specimen in the tube. I always put blood in my CBC tube first if I'm collecting more than one type of tube and a work really fast to get the top on and do the gentle rotation. I tend to hold my breath until the CBC top is on and I've started the gentle rotation. I fill mine to the area between the two lines whether it's a heel stick or venous/arterial sample. We generally do venous sticks for our CBCs but when doing a heel l stick I learned that its best to use the right size lancet... I learned that I really want only the capillary bed to be lanced; if the cut is too deep it can cause the blood to clot faster as the body recognizes the need to send fibrin out faster to start the clotting process. I think I learned this at one of the national nursing conferences. I also learned that when collecting the heel stick CBCs to let a drop of blood enter the tube then gently swirl the tube in my hand as I watch to see another drop form then let that one drop in and again swirl the tube. I learned this from a phlebotomist in my early days. It supposedly starts the blood mixing with the EDTA in the tube to help it not clot.

Fortunately I do not have many CBCs come back clotted and often thought I was the lucky one but now I think it's the shaking thing... I'm going to mention this to my coworkers to see if they might notice a difference if they don't shake theirs as much and do the gentle rotation instead... Thanks for the tip Steve!

:yeah:

NeoNurseTX, RN · Apr 25, 2010

Mine quit clotting after I figured out not to fill it past the 2nd line.

Jokerhill · Apr 29, 2010

We used to fill between the two lines, but according to the lab, they now have new equipment and the tubes have to be filled to the top line. We always hand carry our lab specimens to the lab, we used to use the tube system, but the specimens would get lost.
We still have phone calls that the blood clotted. One problem is the length of time the blood sits in the lab, when the phone call comes an hour later, we know it's been too long!

You are wrong, I worked in hematology for 14 years before going into nursing and now the NICU. If the specimen is good when you it leaves your unit it will be good to run forever. Clotting is a fast process not a slow one. The longer it takes means someone was working harder to get you a result and finally had to give up as the cells were uncountable. The lab does not want to do the test over they already did most of the work but now have to repeat everything they already did, they don't get out of anything they just get more work by redoing the test now how many people want that. There are drawing techniques that help as pointed out but there is nothing the lab can do after the draw to make it better. The intensic and extrensic clotting cascades happen almost immediately not 20 min. later, not even an hour later, if it did there would be a lot of bleeding going on in the OR and at accidents. Look up the average bleeding time if you don't beleave me. It takes 1-9 min. for the cascade to complete and a clot to form but you don't even have to have a full clot to have a bad specimen you can have the begining of the clotting process start causing fibrin strands to form in the specimen making it bad. So you could draw the baby in front of the analyzer and get a bad specimen as I said before clotting happens fast not slow. There is no slow clotting process in a normal human. There are abnormal humans with low or missing clotting factors and anti-coagulated humans but this is not what we are talking about, because their specimens wont be having a clotting problem anyway.

As for the poster who said it was the amount of heparin in the tube if you have heparin in your tubes you are really messing things up. Heparin you see makes those little red cell look like balloons not con-caved disk making the analizer do all kinds of funny things, and I have had nurses add heparin to the specimens before. Fortunately the baby had had a previous collection and the same person read both test saving the family a visit from the oncologist.

NICU_babyRN, BSN, RN · May 1, 2010

1. People put too much blood in the microtainers, depleting all the anticoagulant in the tube. All you need is 300 microliters, between the 1st and second line.
2. Shaking. Lyses RBCs, causing clotting cascade activation.
3. Scraping the heel while obtaining sample: RBC lysis, clotting cascade activation.
So, it's not always the lab's fault, though it is most of the time!

Shaking does indeed lyse. The recommendation given by BD (microtainer brand) is to gently turn the lavender top tube up and down 8 times to mix the blood with the heparin. 300 microliters is indeed all you need!