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2 cell vs 3 cell screen


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We initially switched to a 3 cell screen because it made the transfusion service medical director more comfortable when we went to the immediate spin crossmatch.  That was a long time ago and I don't know if the facility is still using the 3 cell screen or not.  I suspect they are since inertia is the most powerful force in the universe which explains why blood bankers find it nearly impossible to change once the course is set.  (This of course, was typed with a partial smile!)  

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8 hours ago, Dansket said:

3-cell screen might mitigate the poor technique of non-blood bankers who do tube testing, but not necessary for manual or automated gel testing.  All our testing is done on ProVue with 2-cell screen.

Why do you say it might mitigate poor technique? My blood bank experience is mainly gel with 2 cell screens.

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The was a white paper written by John Judd many years ago regarding 2 versus 3 cell screens.  In this study, he observed that technique (tube testing) was a far greater variable affecting test tube reaction strength than the number of cells in the antibody screen.  Since 3 cell screens are configured with more double-dose cells than 2-cell screens, it might mitigate the weaker reactions found by some individuals.

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It depends what type of population you are testing.  If you are testing patients, then ideally you need to have those antigens where antibodies may only react against homozygotes present in a double dose.  It is almost impossible to do that with just two cells - regardless of whether you are testing in gel or in tube.    So, three cells for patients.  Two cells is fine for donors where very weak antibodies are less important

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9 minutes ago, Likewine99 said:

Two cell screen for as long as I can remember.  It saved the organization quite a bit of money and we keep 2 panels in stock.

Have been on gel since 1994 and automated BB analyzer for almost 13 years.

Did you attend ORTHO's very first ProVue training session?  

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On ‎3‎/‎27‎/‎2017 at 7:15 AM, galvania said:

It depends what type of population you are testing.  If you are testing patients, then ideally you need to have those antigens where antibodies may only react against homozygotes present in a double dose.  It is almost impossible to do that with just two cells - regardless of whether you are testing in gel or in tube.    So, three cells for patients.  Two cells is fine for donors where very weak antibodies are less important

I completely agree. I have no intention of switching to 2-cell screen, but these sorts of discussions always give me pause. We identify so many antibodies in patients who are transfused, where the reactions are only identifiable on cells with homozygous expression.

 

On ‎3‎/‎27‎/‎2017 at 8:35 AM, AMcCord said:

The Echo runs a 3 cell screen so we have continued to run a 3 cell screen for tube testing. Sometimes that extra cell means you've got the rule out you need for an antibody ID without running more than one panel on the Echo. 

I am also a fan of free rule out cells on the screen itself.

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For all of those people who have switched to the two cell screen for cost reasons, have any of you had any trouble with patients having acute or delayed haemolytic reactions all over the place (first question) and is cost reasons a valid reason for switching from three to two (second question).  Please be brave enough to answer BOTH questions.

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We have used 3 cell screens since the 90s. We switched from 2 cell to 3 cell when we went to immediate spin crossmatches. I think I remember my boss at the time said 3 would do a better job of detecting antibodies because of more cells with homozygous expression. We also use the screening cells as extra rule-out cells when we can. I don't plan on switching to 2 cell. Someone else can do that after I retire. Don't fix something that ain't broke.

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On ‎3‎/‎28‎/‎2017 at 2:52 PM, Malcolm Needs said:

For all of those people who have switched to the two cell screen for cost reasons, have any of you had any trouble with patients having acute or delayed haemolytic reactions all over the place (first question) and is cost reasons a valid reason for switching from three to two (second question).  Please be brave enough to answer BOTH questions.

It was before my time, but...

1. We don't have hemolytic reactions all over the place. In fact, we rarely have delayed hemolytic reactions at all. It is always very exciting for us - great teaching tool as well for students - when it does happen.  Maybe 1 every 2-3 years?

2. I would assume cost was a big part of the equation. We use gel (manual) so you do use a lot less cards with a 2 cell screen!

s

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As John Staley stated, inertia is the strongest force in the universe!

We've been doing a manual 3 cell since we went to IS XM, same as DebbieL.  And then along came 'electronic XM' (sorry Malcolm) and inertia keeps us at 3 cell.

Automated methods (Neo & Tango) are both 2 cell, but those methods are more sensitive.

As with lots of things in the BB, it all depends on your medical director's comfort level...

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  • 10 months later...

Way back in 2003, the AABB published "Guidelines for Implementing an Electronic Crossmatch". In the section REQUIREMENTS on page 4 "Additional criteria suggested, but not universally accepted, include: ... The antibody screen should include a three- or four-cell sample."

No further explanation was given but presumably it was for the reasons stated above that you are likely to have more cells with a homozygous antigen expression in a 3-cell panel than you are in a 2-cell panel. Most manufacturers of 3-cell panels make sure to include cells that are homozygous for Duffy and Kidd to avoid missing those.

So long story short....that's why we use a 3-cell panel as part of our due-diligence of providing blood by computer assisted crossmatch.

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