Pre-warm and cold panels

[SRMC BB]

I'm in the (neverending) process of reviewing the procedure manual for the year. I've never really liked our prewarm procedure as it was written well before my time here. Does anyone have a procedure they are willing to share to help me out.

Thanks,

Natalie

[Malcolm Needs ☆]

I'm in the (neverending) process of reviewing the procedure manual for the year. I've never really liked our prewarm procedure as it was written well before my time here. Does anyone have a procedure they are willing to share to help me out.

Thanks,

Natalie

I'll try to post something properly tomorrow. I'm a bit busy tonight, having been at a meeting all day, and have come home to a sick son.

:eek::eek:

[adiescast]

Sorry to hear your son is sick, Malcolm!

[Malcolm Needs ☆]

Sorry to hear your son is sick, Malcolm!

Thanks for that. It is nothing major, justa bout of nausea (but messy)!

:eek::eek:

[tbostock]

I'm not a fan of prewarming; I think it should be used as a last resort after every effort has been made to rule out clinically significant antibodies first. So...see attached for my SOP.

Prewarm Technique 3-7.doc

[OPUS104]

Instead of pre-warming, how many ppl use the REST reagent? We basically almost never use pre-warming Terri.

[Malcolm Needs ☆]

Instead of pre-warming, how many ppl use the REST reagent? We basically almost never use pre-warming Terri.

I know where you're coming from, and it is an exceptionally useful tool, but it does take out more than just "cold" antibodies (anti-B for a start), and so they actually say (or, at least, the last time I looked they said) in their package insert that you should not use plasma/serum adsorbed with REsT to cross-match, whereas pre-warming, warm-washing doesn't remove antibodies that react strictly at 37oC.

:redface::redface:

[adiescast]

We don't use any adsorption method unless there is no other legitimate way to obtain non-reactive cells. Adsorption changes the picture away from what is actually happening in vivo by making an artificial change in vitro. If you are not careful, it can give you a false sense of security about your transfusion.

Don't get me wrong, I like adsorption techniques for clearing the picture. You just have to be careful...just like you have to be careful with pre-warming, saline replacement, and different enhancement techniques.

[Malcolm Needs ☆]

I'll try to post something properly tomorrow. I'm a bit busy tonight, having been at a meeting all day, and have come home to a sick son.

:eek::eek:

I don't think that I can improve on Terri Bostock's method; it looks fine to me, so I am not even going to try.

:D:D:D:D

[rravkin@aol.com]

I am wondering if pre-warm should be the primary technique as opposed to the RT, to 37C inc, and back to RT to finish. Pre-warm would more closely mimic the in-vivo state without any alteration of molecules from that state and thus give us better capability to prepare transfusable products. I think that our current processes being born out of RT data and techniques have created a convention for which we may not be able to break any time soon. I know that there were some previous threads that talked about the many anomaly reactions that we are forced to work up and lead to no clinically relavant solution. With the advent of automation in the BB I wonder if prewarming may soon become the convention because I believe it would be relatively simple to add heating elements such that your reactants could be prewarmed; especially when using GEL. I am no expert, and I realize that there may be some missed items but I would think it much more loggical to replicate the environment for which we want to know most about; and also with instrumentation in the BB there could also be a time when these reactions are run in the abscence of light. Let me know what you think; and thank you in advance.:)

[Malcolm Needs ☆]

I am wondering if pre-warm should be the primary technique as opposed to the RT, to 37C inc, and back to RT to finish. Pre-warm would more closely mimic the in-vivo state without any alteration of molecules from that state and thus give us better capability to prepare transfusable products. I think that our current processes being born out of RT data and techniques have created a convention for which we may not be able to break any time soon. I know that there were some previous threads that talked about the many anomaly reactions that we are forced to work up and lead to no clinically relavant solution. With the advent of automation in the BB I wonder if prewarming may soon become the convention because I believe it would be relatively simple to add heating elements such that your reactants could be prewarmed; especially when using GEL. I am no expert, and I realize that there may be some missed items but I would think it much more loggical to replicate the environment for which we want to know most about; and also with instrumentation in the BB there could also be a time when these reactions are run in the abscence of light. Let me know what you think; and thank you in advance.:)

I agree that it is the best method for replicating in vivo conditions, but it does take time.

:)

[rravkin@aol.com]

I agree that it is the best method for replicating in vivo conditions, but it does take time.

:)

Hey Malcolm,

Thank you for your comment. I wanted to know if you were aware of any BB instrumentation being developed around a prewarm format of testing? (and with the abscence of light) :)

[Malcolm Needs ☆]

Hey Malcolm,

Thank you for your comment. I wanted to know if you were aware of any BB instrumentation being developed around a prewarm format of testing? (and with the abscence of light) :)

I'm afraid not.

:o:o

[lalamb]

Our step by step is essentially the same. We used to do prewarm automatically when all 3 screening cells were weak/sticky, but our ref lab always warned against junping into a warm techneique, cuz significant ab's could be missed.

We don't have prerequisite conditions before prewarming can be done. I like the ones in your P&P and will see about adding them. thanks

[Malcolm Needs ☆]

but our ref lab always warned against junping into a warm techneique, cuz significant ab's could be missed.

I keep reading this (not just on BBT), but has anyone actually seen an antibody that has been pre-warmed away and actually caused a haemolytic transfusion reaction with clinically significant sequalae, or is it just a case of this may happen, because some of the antibodies found in testing when the reactants are mixed "cold" have specificities that make us think that they are significant? I am aware of John Judd's papers, and those of George Garratty, but none of them (that I have read anyway) quote a convincing case where transfused blood, cross-matched by the pre-warmed method, has caused an antibody/antigen clinically significant haemolytic transfusion reaction that was detrimental to the patient.

I am more than ready to stand corrected.

:confused::confused:

[tbostock]

I'll repost this link for those who haven't seen it; a nice discussion of prewarmed and why to be cautious.

http://www.cbbsweb.org/enf/2009/prewarm_missab.php

Good point, Malcolm...looks great on paper, but has anyone actually seen one?

[rravkin@aol.com]

I'll repost this link for those who haven't seen it; a nice discussion of prewarmed and why to be cautious.

http://www.cbbsweb.org/enf/2009/prewarm_missab.php

Good point, Malcolm...looks great on paper, but has anyone actually seen one?

Terri,

The article presented here does not commit to weather a missed Ab using Pre-Warm technique has the capability of causing a hemolytic transfusion reaction. It is the level of reactivity in the in-vivo setting that is most significant when considering campatible cellular products.:)

[Malcolm Needs ☆]

I'll repost this link for those who haven't seen it; a nice discussion of prewarmed and why to be cautious.

http://www.cbbsweb.org/enf/2009/prewarm_missab.php

Good point, Malcolm...looks great on paper, but has anyone actually seen one?

Thanks for the link Terri.

I have now read the discussion, and still say that the contributors are talking about potentially clinically significant antibodies, even if the specificity of the particular antibody is "known to be clinically significant".

They still do not cite a case where an actual clinically significant haemolytic transfusion episode has actually taken place.

I remain sceptical.

:confused::confused:

[Fluffy agglutinates]

I am wondering if pre-warm should be the primary technique as opposed to the RT, to 37C inc, and back to RT to finish. Pre-warm would more closely mimic the in-vivo state without any alteration of molecules from that state and thus give us better capability to prepare transfusable products. I think that our current processes being born out of RT data and techniques have created a convention for which we may not be able to break any time soon. I know that there were some previous threads that talked about the many anomaly reactions that we are forced to work up and lead to no clinically relavant solution. With the advent of automation in the BB I wonder if prewarming may soon become the convention because I believe it would be relatively simple to add heating elements such that your reactants could be prewarmed; especially when using GEL. I am no expert, and I realize that there may be some missed items but I would think it much more loggical to replicate the environment for which we want to know most about; and also with instrumentation in the BB there could also be a time when these reactions are run in the abscence of light. Let me know what you think; and thank you in advance.:)

Saw this baby at the BBTS conference last year & was amazed by it! http://diamedil.info/info/IH_1000__Presentation.pps#258,1,Welcome to the Future

Most of the automated machines in use currently in the UK do have heated blocks which the cards sit in (either at 37 or 22oC). Main problem is the samples & reagents are 'cold' - so can't do a true prewarm by automation.

[rravkin@aol.com]

Saw this baby at the BBTS conference last year & was amazed by it! http://diamedil.info/info/IH_1000__Presentation.pps#258,1,Welcome to the Future

Most of the automated machines in use currently in the UK do have heated blocks which the cards sit in (either at 37 or 22oC). Main problem is the samples & reagents are 'cold' - so can't do a true prewarm by automation.

I know about the heat blocks; mechanically it would be very simple to install heated aspiration aperatus for the reagents and cause a slight delay to warm the volume of each; but conventionally we are potentially looking at rethinking a century plus worth of data. Not impossible but very time consuming.:)