What does your facility do when you have platelet clumping?

[TVC15]

Thanks Alan that is very interesting! I wonder if that product will head over to the US anytime soon...or is it possibly already here?

Thanks for posting it!

[TVC15]

I emailed the company to inquire if this product was available in the US and this was their response:

Thank you for your interestin our ThromboExact S-Monovette. Unfortunately, we are not selling theThromboExact in the USA and have not yet sought regulatory510(k) clearance. If you have any furtherquestions please do not hesitate to contact us.

[Joseph]

I have been vortexing CBC samples for many years. Try it. It doesn't cause fragmentation, won't lyse cells and won't cause any issues with the CBC. It does break up those platelet clumps caused by improper collections like short draws, hard sticks in the ER, etc. It doesn't break up the clumping from EDTA sensitivity. Try it. Compare the WBC and RBC before and after, make smears if you want to. It works!

[MT15]

We have also validated vortexing in our lab years ago. We saw no differences in WBC, RBC or indices between pre-vortexed and post-vortexed runs. Slides made post-vortexing show no red cell fragmentation, we do check every vortexed specimen with a slide. When you think about it, red cells are really not fragile and must do extreme contortions to fit through the capillaries.

When I first heard about it, I had a similar opinion to TVC15, but luckily we tested it out for ourselves before making assumptions. It's really rewarding to learn something new, test it out, and put it into practice. We save some patients the trouble of a recollection this way.

[TVC15]

We have also validated vortexing in our lab years ago. We saw no differences in WBC, RBC or indices between pre-vortexed and post-vortexed runs. Slides made post-vortexing show no red cell fragmentation, we do check every vortexed specimen with a slide. When you think about it, red cells are really not fragile and must do extreme contortions to fit through the capillaries.

When I first heard about it, I had a similar opinion to TVC15, but luckily we tested it out for ourselves before making assumptions. It's really rewarding to learn something new, test it out, and put it into practice. We save some patients the trouble of a recollection this way.

Hi I am not only concerned about the red cells lysing. But actually red cells that have reached their life span will lyse easily. And on top of that certain cancer, sickle cell and anemic patients do have fragile RBC's. Also what about WBC fragmentation? How do you know that you are counting true platelets and not RBC or WBC fragments after vortexing?

I am all open to learning new things but logically this just does not sound like a good practice.

Edited January 15, 2013 by TVC15

[MT15]

We have never seen RBC or WBC fragments on a slide after vortexing EDTA samples. The RBC and WBC counts do not decrease between the runs before and after vortexing and are well within what you would expect between replicate runs on the same sample.

Whether the technique seems logical or not is an opinion. Until an opinion is tested, it is only an opinion, not a fact. I was surprised to discover that vortexing does not damage the cells, but the results were clear. Try it for yourself if you want proof. It isn't hard to test it out. Take some CBCs that you have just finished with, and vortex them for about a minute on the highest setting. Then immediately rerun the tube. Compare your WBC, RBC, and PLT counts before and after the vortexing. We found no significant difference. We do exempt hem-onc patients from this practice, even though we found no differences there either, I think it was just to make the pathologist feel better.

I will say it usually only works on patients who have no other major issues, but the collection was less than optimal resulting in a small amount of platelet agglutination, but no apparent clot. Just enough to cause the analzyer to flag for platelet clumping. It's not a magic trick, it won't clear up EDTA platelet clumping, and if it doesn't work, you can always recollect anyway.

[TVC15]

We have never seen RBC or WBC fragments on a slide after vortexing EDTA samples. The RBC and WBC counts do not decrease between the runs before and after vortexing and are well within what you would expect between replicate runs on the same sample.

Whether the technique seems logical or not is an opinion. Until an opinion is tested, it is only an opinion, not a fact. I was surprised to discover that vortexing does not damage the cells, but the results were clear. Try it for yourself if you want proof. It isn't hard to test it out. Take some CBCs that you have just finished with, and vortex them for about a minute on the highest setting. Then immediately rerun the tube. Compare your WBC, RBC, and PLT counts before and after the vortexing. We found no significant difference. We do exempt hem-onc patients from this practice, even though we found no differences there either, I think it was just to make the pathologist feel better.

I will say it usually only works on patients who have no other major issues, but the collection was less than optimal resulting in a small amount of platelet agglutination, but no apparent clot. Just enough to cause the analzyer to flag for platelet clumping. It's not a magic trick, it won't clear up EDTA platelet clumping, and if it doesn't work, you can always recollect anyway.

Sorry but I don't work in heme. I have only worked as a Reference Lab Blood Banker but was trained at a very top notch cancer center as a generalist. We received a very thorough and solid training in hematology. This practice was never done in that lab and when I called to ask the seasoned Hematologists after seeing a CLS doing this they were also surprised at this practice. I have found zero literature other than one very old paper that recognizes or supports this practice.

I now work as a CLIA consultant.

My question is how do you know that some of the WBC organelle fragments are not being stained and counted as PLT's.

You say that after vortexing you see no significant difference then why do it to begin with?

Also how do you know if a first time patient in the ER has no major issues?

Edited January 15, 2013 by TVC15

[jayinsat]

This is taken from a CAP competency this year.  I find it interesting that they seem to imply that vortexing the sample may be a valid tool.

http://ocatp.medialabinc.net/courses/s_page.aspx?step=9&cassignment=5675288&cassignmenthash=a2b90633421f09dcb7634dffe9a3826d&oid=4701443&o=fb5102c0cdd8152617c4f01af58eccf9

 

    2014 Pro Course: White Blood Cells

 

 

 

Identify non-white blood cell particles that may interfere with automated white blood cell counts and interpret general instrument flagging messages.

Particle Interference: Platelet Clumping

In many laboratories, platelet clumps are a more common interference with accurate WBC counting than NRBCs or lyse-resistant RBCs. Image 1 shows clumps of platelets in a peripheral smear. Platelet clumps in peripheral blood samples are most often due to preanalytic errors, such as inadequate or delayed mixing of the sample after collection. Platelet clumping can also occur in patients with antibodies that can bind to platelets and are activated by EDTA.

 

Image 1

Individual platelets normally shrivel and disappear when exposed to the lysing reagents used to obtain automated WBC counts. However, when clumps of platelets are present, the lyse used may not be strong enough to shrink these clumps to a size that will not interfere with the WBC count. This is especially true if the instrument uses a "soft" lyse. Analyzers that use a "hard" lyse to determine the WBC count are less likely to have inaccurate WBC results due to platelet clumps.

In extreme cases, the platelet clumps may be large enough that they appear at or beyond the feather edge, rather than in the body of the smear. The feather edge of the smear should always be examined when platelet clumps are suspected, i.e., WBC interference or an unexpected low platelet count. Image 2 shows numerous large clumps at the very edge of the smear.

 

Image 2

It is not always possible to distinguish WBC count interference caused by platelet clumps from that caused by lyse-resistant RBCs or NRBCs, as all three may appear at or near the same area on scattergrams and histograms. It is imperative to understand and correctly interpret histogram and scattergram displays on the analyzer in use.

Platelet clumps can often be dispersed by vortexing the sample for 30-60 seconds and quickly reanalyzing. However, if interference is still evident, an alternate method must be used to obtain an accurate WBC count, such as collecting a new sample with a tube containing sodium citrate anticoagulant.

 

 

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[SMILLER]

Having read an article several years ago about this practice, we have been using it when necessary, such as when a redraw is unavailable. 

 

If you are going to vortex for less than a minute, you may as well not bother.  Also, we have not seen any problems with other parameters being affected by vortexing.

 

For EDTA clumpers, it really doesnt work so well.  Even with regular patients with clumping due to phlebotomy trauma or whatever, sometimes all of the platelets do not dissociate after vortexing.  Likewise, it does nothing for those small fibrin clots. 

 

It is important that you make a smear AFTER vortexing to check for any remaining clumps (just because the platelet count goes up after vortexing doesnt mean that ALL the clumps are gone!)

 

Scott

[gilmanch]

Hello, opening this topic back up!

 

My last lab, when we used a citrate tube for platelet clumping, we would multiply the WBC. RBC. HGB, HCT AND PLT RESULTS BY 1.1 and then manually calcuated the MCH and MCHC. At my current place the prodedure says "multiple parameters by 1.1" not specifing the "s" on parameters so everyone here just does the PLt count and that is it. Maybe this is more instrument dependant or just an unclear procedure that failed us here. I dont really know why we would do all the parameters to justify my case for how my previous lab would do it.

 

Any help would be great! Thx!

 

Christen

[Auntie-D]

Hello, opening this topic back up!

 

My last lab, when we used a citrate tube for platelet clumping, we would multiply the WBC. RBC. HGB, HCT AND PLT RESULTS BY 1.1 and then manually calcuated the MCH and MCHC. At my current place the prodedure says "multiple parameters by 1.1" not specifing the "s" on parameters so everyone here just does the PLt count and that is it. Maybe this is more instrument dependant or just an unclear procedure that failed us here. I dont really know why we would do all the parameters to justify my case for how my previous lab would do it.

 

Any help would be great! Thx!

 

Christen

 

I don't like doing it this way as it only works for patient with a normal RBC. When I was in charge (I've moved now so am no longer) we divided the RBC from the EDTA sample by the RBC from the citrated sample and then multiplied the platelets by this - this took into account the MCV/PCV.

 

Does your facility receive samples in tandem or just a citrate - if you receive tandem samples you should only really be reporting the parameters from the EDTA, bar platelets. In our current lab if we receive a citrate alone we only offer a platelet count (mutiplied by 1.1)

Edited February 11, 2015 by Auntie-D

[SMILLER]

We would normally only use the citrate resulst for the platelet count, after multiplying by 1.1 (or dividing by 0.9!).  EDTA results are best for most analyzers as far as differentails I believe.

 

We try to maintain a list of inpatients and repeating outpatients who are known EDTA clumpers so that a citrate is drawn with every CBC or platelet count.

 

Scott

[nziegler]

We request tandem samples for the redraw and use the blue only for the platelets. Of course, this requires education of dozens of processors so that we actually RECEIVE the extra blue top back to hematology.... but we're getting better!

[Auntie-D]

We request tandem samples for the redraw and use the blue only for the platelets. Of course, this requires education of dozens of processors so that we actually RECEIVE the extra blue top back to hematology.... but we're getting better!

 

And unspun...