Hi,

I love this forum and have been "lurking" for quite some time!  I have a question for those who perform elutions.

Do you test the eluate with a set of screening cells first or do you go directly to testing against a panel?  Does it depend on how much eluate you have?

I have worked at a few different places and have seen it done both ways so I'm just curious if there is a significant bias one way or the other.

Thanks!

Where I worked, we always went straight for the panel.

 

For me, it's completely dependent upon the results I obtained in my serum/plasma testing and the amount of eluate I have to test.

do the screening cells/control cells first--then if neccessary-panel

 

We go straight for the panel, we're an IRL so I don't know if it's different between hospital and reference lab?

A good serologist is an efficient serologist. Do the small work first - the screen. Only do the panel if the screen is reactive and you need more information.

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected.  But by doing the screen you are saving reagent/cost.  I'm not sure there is a right or wrong answer to this question?

Depends on the results of the investigation thus far.  But either way, you might need to add A and B cells!  You might be worrying about a reaction due to ABO incompatible PLT or IVIG!

 

55 minutes ago, jmm8427 said:

One could argue that by doing the panel first you are being efficient and potentially saving time with antibody identification if something is detected.  But by doing the screen you are saving reagent/cost.  I'm not sure there is a right or wrong answer to this question?

Rhetorical question: Is it a typical request for a "Type & Panel" ?

If you are almost certain that the eluate will be reactive, I agree that the screen may be redundant. However, it is still a test against phenoptyped cells and the information is still valuable even if you end up testing a panel.

In pediatrics we often struggle to get an adequate sample, so most of the time we go directly to the panel.

Generally, we do the screen first.  They are often negative, then as far as possibly wasting reagents (and more importantly in an acute care setting--time), you are NOT running a full panel that would have been negative.

And like a returning patient with a known positive atypical antibody history, if the screen is positive, you can use the screen cell results for rule outs/rule ins.

Scott

51 minutes ago, SMILLER said:

Generally, we do the screen first.  They are often negative, then as far as possibly wasting reagents (and more importantly in an acute care setting--time), you are NOT running a full panel that would have been negative.

On the other hand, in an acute situation, if the screen is positive, you are wasting time doing the screen, because you will then have to go on and do the panel while the patient is still bleeding.

46 minutes ago, Malcolm Needs said:

On the other hand, in an acute situation, if the screen is positive, you are wasting time doing the screen, because you will then have to go on and do the panel while the patient is still bleeding.

A fair point, Malcolm.

So, I once again pose the rhetorical question: In an acute situation, do you do a "Type & Screen" or a "Type & Panel" ????

Equally good point.  A type and screen, but this is on the grounds that, in all but the most acute of acute haemolytic transfusion reactions, the reaction can be treated, whereas a patient who has bled to death cannot be resurrected!

Edited September 15, 20177 yr by Malcolm Needs

I agree that it depends on the results of the workup up to the point of the elution.  I typically do the screen first. 

We do the screen and the panel right away if there is enough eluate to go around, however our policy also states that if the DAT results have not changed from previous time and no new antibodies have formed, an eluate does not need to be performed. We have a lot of cancer patients on weird meds that mess with the DAT so it would be a supreme waste of reagent to do it over and over to achieve the same "All cells reacting, no specificity" results.

Interesting responses.... I've seen it done both ways as well.  My reference lab experience has been to go directly to the panel while my hospital experience has been to perform the screens first.

Edited September 15, 20177 yr by jeloweryii

Another question on eluates - we often get apparent "panagglutinins" when testing eluates.  Our policy has been to send these samples to our Reference Lab because we cannot perform rule outs.  Is this appropriate or over the top?  I kind of like the terminology "newbie" used "All cells reacting, no specificity". 

I think one has to be very careful when answering your question Byfaith.

If you know ABSOLUTELY that it is an auto-antibody, such as an auto-anti-Hr^B, or something like that, then, unless you have a selection of reagent red cells that are Hr^B- ot Rh_null, it is a waste of time sending them to most Reference Laboratories, because it is unlikely that they will have access to these rare cells either.

On the other hand, if you have not got that certainty, and the auto is either negative, or the patient has been recently transfused and the DAT is negative, then it maybe far from a waste of time sending the sample to a Reference Laboratory.  Under such circumstances, the antibody could be directed against a high prevalence antigen, either a very clinically significant one, such as Vel, or one of somewhat less clinically insignificance, such as anti-hr^B, which may cause a delayed haemolytic transfusion reaction, but is so "low key" as to mimic a serological transfusion reaction, but which could, nevertheless, be avoided given correct identification of both the antibody specificity and suitable donors.

Not withstanding the need for completing this vital work by chosen means available, if the transfusion of this patient becomes a life or death issue, as determined by the patient's physician, then the patient's physician would sign for uncrossmatched ABO/Rh compatible PC's.

13 hours ago, Malcolm Needs said:

I think one has to be very careful when answering your question Byfaith.

If you know ABSOLUTELY that it is an auto-antibody, such as an auto-anti-Hr^B, or something like that, then, unless you have a selection of reagent red cells that are Hr^B- ot Rh_null, it is a waste of time sending them to most Reference Laboratories, because it is unlikely that they will have access to these rare cells either.

On the other hand, if you have not got that certainty, and the auto is either negative, or the patient has been recently transfused and the DAT is negative, then it maybe far from a waste of time sending the sample to a Reference Laboratory.  Under such circumstances, the antibody could be directed against a high prevalence antigen, either a very clinically significant one, such as Vel, or one of somewhat less clinically insignificance, such as anti-hr^B, which may cause a delayed haemolytic transfusion reaction, but is so "low key" as to mimic a serological transfusion reaction, but which could, nevertheless, be avoided given correct identification of both the antibody specificity and suitable donors.

Thanks for your response!  So another somewhat gray area - sounds like we will continue our practice of having our IRL work them up.

We go straight to the panel. Do not always have enough to do both if the screen is positive.

On ‎09‎/‎15‎/‎2017 at 9:41 AM, Malcolm Needs said:

On the other hand, in an acute situation, if the screen is positive, you are wasting time doing the screen, because you will then have to go on and do the panel while the patient is still bleeding.

When I used the term "acute-care setting" I was referring to the facility, as in a hospital (versus a reference lab).  Where the extra time it takes to do a panel (if it may not be needed in non-critical cases) might be a consideration.  We would indeed probably just do a panel to save time if someone was bleeding to death, or at least do both at the same time.  (Generally, I would think that most reference labs do not have patients in "acute situations" lying about!)

Scott

I would always go directly to a panel.  It is not that much more labor intensive that running the screening cells first.  At my current facility the need for elution studies is rare and all are sent out.

I evaluate the individual case to determine what cells might be the most informative. In practical terms, most of the time I go straight to a panel. If it was a cord blood sample, then I'd consider A and B cells plus either a panel or screen. (Haven't done an eluation on a cord blood panel in years and years.)