CBC clotting

CLSPVH · Dec 8, 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!

This is a quote from nurse.com. Just wanted to let you know that there are many nurses out there that actually do understand about clotting and that if a specimen is really clot free, then it is REALLY clot free.

" The lavender-top tube used for the CBC contains the additive EDTA, which neutralizes the calcium in the specimen and prevents blood from coagulating. A CBC specimen can end up clotted and unusable, **however; the problem usually occurs at the time of collection. **The

additive must mix thoroughly with blood when the specimen is collected. In addition, if blood collection is a slow process (perhaps in the case of a difficult draw or sluggish central line), **the clotting process could begin before the blood enters the tube.** (Just because your CBC is "runny" when walk it down to the lab doesn't mean the initiation of the clotting cascade hasn't begun. You cannot see microscopic clots with the naked eye) If a syringe full of blood is set aside while a central line is flushed or some other activity is performed, the blood has a greater opportunity to clot. For best results, transfer blood immediately from the syringe to an appropriate tube and invert the tube several times."

So if a phlebotomist from the lab draws a specimen that ends up clotted, then yes, it is someone from the lab's "fault". However, if it is a RN or LPN or someone outside of lab that draws a specimen that ends up clotting, then I'm afraid you cannot lay the blame with the lab.

CLSPVH · Dec 8, 2010

Thank you for an educated response. It's great to know that there are nurses out there who really do understand how and why a specimen clots. It's refreshing to hear something besides ... "It must have been the lab's fault."

aerorunner80, ADN, BSN, MSN, APRN · Dec 18, 2010

The only time I've noticed a problem with my CBC's clotting (I'm talking when I get a phone call from lab) is when I'm drawing them on either a minutes old or 1-2 hour old infant when the baby is making it's transition from intrauterine to extrauterine life.

Any other time, if it's going to clot I notice it while I'm drawing it because it happens so quickly. When this happens it's typically my own fault because I haven't been rotating the tube lke I should.