Reference lab workups

[keisterkid]

Our current SOP requires that each workup is done in two media, either

• LISS panel with all negative reactions tested using PEG
  
• 22% albumin panel with all negative reactions tested using PEG
  
• or the method used by client (ex. GEL) and negative reactions tested using PEG
  

Do other reference labs always use two media? We are thinking of using PEG as the primary potentiator and if we aren't able to solve the problem then resort to the other methods. This is a cost cutting/time saving idea but we want to hear what other reference labs are doing....

[OPUS104]

This is from a small facility, (so take it for what its worth) we only use different media if the results aren't clear cut. Some people we talk to start with two medias at the beginning, but we have not seen the need if it turns out to be a straight up Kell or E. If we carried it to extreme, we would be doing full panels on every donor/pt instead of just screens. Having said that, it does seem to be an odd workup anymore that doesnt have at LEAST two medias.

[David Saikin]

Also a small reference facility . . . I work in gel. If your clients work in gel and you do not, chances are, unless the ab is strong (3/4+), you will not find it in PeG. My experience is that gel reactions of 2+ or less are NOT detectable with tube testing, regardless of the enhancement. Working with 2 different media seems like a waste of resources and time. I also maintain stock of various tube enhancement media in order to duplicate client results if possible, but my job is to identify problems not make extra work.

[keisterkid]

Also a small reference facility . . . I work in gel. If your clients work in gel and you do not, chances are, unless the ab is strong (3/4+), you will not find it in PeG. My experience is that gel reactions of 2+ or less are NOT detectable with tube testing, regardless of the enhancement. Working with 2 different media seems like a waste of resources and time. I also maintain stock of various tube enhancement media in order to duplicate client results if possible, but my job is to identify problems not make extra work.

Just a sidebar as to why we use PEG: We did testing for a tube manufacturer, wanting to bring plastic BB tubes to market, for all common clinically significant alloantibodies and found that, in our hands, PEG gave consitently stronger reactions and for a longer time. The testing was done at 3, 7,10,14 and 21 days.

[BBK710]

Also a small reference facility . . . I work in gel. If your clients work in gel and you do not, chances are, unless the ab is strong (3/4+), you will not find it in PeG. My experience is that gel reactions of 2+ or less are NOT detectable with tube testing, regardless of the enhancement. Working with 2 different media seems like a waste of resources and time. I also maintain stock of various tube enhancement media in order to duplicate client results if possible, but my job is to identify problems not make extra work.

I agree completely. As a client it is extremely frustrating when we send a sample for identification to our reference lab and they tell us that it is negative when we had positive reactions in gel. Then they will test in gel for an additonal charge and only when one of their "gel techs" are available. Doesn't help the patient who is waiting for a safe transfusion.

[Eagle Eye]

Also a small reference facility . . . I work in gel. If your clients work in gel and you do not, chances are, unless the ab is strong (3/4+), you will not find it in PeG. My experience is that gel reactions of 2+ or less are NOT detectable with tube testing, regardless of the enhancement. Working with 2 different media seems like a waste of resources and time. I also maintain stock of various tube enhancement media in order to duplicate client results if possible, but my job is to identify problems not make extra work.

Your facility is too far from where I am. I want some one who uses gel...we go through exact same thing as you said. We find Positive in Gel and ref. comes back with "all clinically significant antibodies ruled out". Sometime they would do gel and will say 3 out of 11 cells reacted in Gel with no conclusion as to what is the antibody...So many time we feel like giving crosmatch compatible blood by gel is better than sending specimen to ref. lab and wasting time and resources(at least when there ids no h/o recent rransfusion).

[heathervaught]

Our Reference Lab implemented Gel a few years ago for many of the reasons discussed here - when the customer performs their initial workup in Gel (however far they may go with it), we want to be able to continue the workup in Gel. They will often use other media too, in order to help describe the reactivity of any antibodies present, but I think if the customer uses Gel, they will at least start their extended workup that way.

[keisterkid]

Our Reference Lab implemented Gel a few years ago for many of the reasons discussed here - when the customer performs their initial workup in Gel (however far they may go with it), we want to be able to continue the workup in Gel. They will often use other media too, in order to help describe the reactivity of any antibodies present, but I think if the customer uses Gel, they will at least start their extended workup that way.

I don't disagree with the comments about using GEL, we try to duplicate our clients results with GEL if that is what they used. But for the sake of discussion, what are the reference labs to do when a large group of their clients begin using ECHOs? Will clients expect us to purchase ECHOs so we can duplicate their work? At what point do we stop being lead around by blood bank companies/suppliers coming out with new and better "must have" technologies every 5 to 10 years? In my area we now have approx. 7 hospitals that are using or validating their ECHOs.

[Malcolm Needs ☆]

I don't disagree with the comments about using GEL, we try to duplicate our clients results with GEL if that is what they used. But for the sake of discussion, what are the reference labs to do when a large group of their clients begin using ECHOs? Will clients expect us to purchase ECHOs so we can duplicate their work? At what point do we stop being lead around by blood bank companies/suppliers coming out with new and better "must have" technologies every 5 to 10 years? In my area we now have approx. 7 hospitals that are using or validating their ECHOs.

Yes, we've got quite a few in our region, and we have seen an enormous increase in the number of samples sent in with "weak unidentifed antibodies" that we are just unable to confirm by all of our usual techniiques. Personally, I regard them as carp (whoops, I've mis-spelled that I think), because, whatever else they may be, they are NOT going to be clinically significant - so we just ignore them. We have not had a single case yet (I'm talking well over a hundred) that has caused ANY post-transfusion DAT positives yet (serological transfusion reactions), let alone a delayed or acute haemolytic transfusion reactions.

It is a case of sensitivity over sensibility!

:(:(:(

[adiescast]

We don't have gel, so we have run into cases where the client saw something in gel that we can't duplicate in any other method. At that point, I would recommend that they transfuse on Malcolm's principle that nothing bad has happened yet in those scenarios. As we used to say in the old days...transfuse them and the antibody will declare itself. If the client is not comfortable with that, I offer to send it out to a "real" reference lab if they want to pay that fee.

[David Saikin]

Whether one uses gel or capture . . . my feelings are that these systems are way too sensitive hence we users of both products are seeing reactions which waste time and resources. As a gel user I have been fortunate in not being plagued by the cell 2 phenomenon. i have had discussions with Ortho techinical folks . . . Personally, I feel these are some type of HTLA Ab as the few that I have seen (or worked up as referrals) have been in multiply transfused/pregnant individauls AND the majority are ficin sensitive. Do we need to find these? (rhetorical question). Then again we have the question of D typings - 2-3+ in gel some folks are calling Rh Negative. Yes some are definitely weak Ds, but are we confusing the issue? Too sensitive . . .

[rravkin@aol.com]

Yes, we've got quite a few in our region, and we have seen an enormous increase in the number of samples sent in with "weak unidentifed antibodies" that we are just unable to confirm by all of our usual techniiques. Personally, I regard them as carp (whoops, I've mis-spelled that I think), because, whatever else they may be, they are NOT going to be clinically significant - so we just ignore them. We have not had a single case yet (I'm talking well over a hundred) that has caused ANY post-transfusion DAT positives yet (serological transfusion reactions), let alone a delayed or acute haemolytic transfusion reactions.

It is a case of sensitivity over sensibility!

:(:(:(

You got that right Malcom; and very well said. Sometimes less sensitivity is better; and a better comparison. However, if a very sensitive technique is utilized that is Pos initially at a hospital BB and the specimen is sent to a Ref. BB where they use a less sensitive procedure and is Neg were's the tie breaker. It would seem necessary for the Ref lab to employ a least two techinques if they initially aquire a negative result. Without we are really just left with two methods and two different results. Why should we suppose that one of these two results is correct; and if this is where we are left then I would think it far better to call the False Positive then the False negative.

This is a very interesting delema in our practice.:)

[Malcolm Needs ☆]

You got that right Malcom; and very well said. Sometimes less sensitivity is better; and a better comparison. However, if a very sensitive technique is utilized that is Pos initially at a hospital BB and the specimen is sent to a Ref. BB where they use a less sensitive procedure and is Neg were's the tie breaker. It would seem necessary for the Ref lab to employ a least two techinques if they initially aquire a negative result. Without we are really just left with two methods and two different results. Why should we suppose that one of these two results is correct; and if this is where we are left then I would think it far better to call the False Positive then the False negative.

This is a very interesting delema in our practice.:)

I do see from where you are coming rravkin (Why should the Reference Laboratory be so egocentric as to think that their methods are the gold standard, and others do not matter?), but the fact is that the fact that their have been no clinical sequalae does, in a way, validate the method as being senstive enough.

In many such cases, the Hospital Blood Bank will request us to cross-match the blood for them, and we have yet to come across an incident of a clinically significant transfusion reaction.

:confused::confused:

Edited June 26, 2010 by Malcolm Needs
Poor punctuation; for a change, the spelling [UK English] was reasonably okay!

[OPUS104]

I think we can all agree that there is not a "catch-all, be-all" method. Having said that, we have seen quite a few samples come in as "just two very weak cells" in tube for us to work-up the next morning. Then when we call to tell them it is a straight-up anti-E that only shows on homozygous cells in Gel.... well thats usually not good when they transfused 3 "crossmatch compatible" units the night before. Do I have post-transfusion info? No. But I think we can all agree these can not be good situations. (I am aware of one fairly serious post-rxn involving a Kell)

[adiescast]

I think we can all agree that there is not a "catch-all, be-all" method. Having said that, we have seen quite a few samples come in as "just two very weak cells" in tube for us to work-up the next morning. Then when we call to tell them it is a straight-up anti-E that only shows on homozygous cells in Gel.... well thats usually not good when they transfused 3 "crossmatch compatible" units the night before. Do I have post-transfusion info? No. But I think we can all agree these can not be good situations. (I am aware of one fairly serious post-rxn involving a Kell)

It would be very interesting to look at the post transfusion data in a case like this to see if there is anything to the fear that the Coombs crossmatch is not sufficient to provide compatible blood in a patient with a gel-only or solid phase-only antibody

[OPUS104]

When we have antibodies that we can only ID in one media, it doesnt bother me. (even if it doesnt make sense, like something neg. in Gel but 2+ in LISS) What bothers me, is 3 cells reactive out of 45 in PEG and EVERYTHING else is negative. Enzymes, LISS, Gel, 6 Coombs Xmatch all neg. Thats when I worry. My lack of knowledge and exp. (I have only been blood banker for 10 years) keeps me second guessing myself late into the evening sometimes. I notice many of the workups we receive that are only detectable on homozygous cells in Gel, are on older women (to me that is 75 and older) who have history of multiple pregs. I wonder how clinically significant these are when they get transfused on negative crossmatches. At some point I guess we just have to say, "we have done as much (within reason) as we can to make this transfusion safe " and pray HE will take care of the rest.

[Malcolm Needs ☆]

When we have antibodies that we can only ID in one media, it doesnt bother me. (even if it doesnt make sense, like something neg. in Gel but 2+ in LISS) What bothers me, is 3 cells reactive out of 45 in PEG and EVERYTHING else is negative. Enzymes, LISS, Gel, 6 Coombs Xmatch all neg. Thats when I worry. My lack of knowledge and exp. (I have only been blood banker for 10 years) keeps me second guessing myself late into the evening sometimes. I notice many of the workups we receive that are only detectable on homozygous cells in Gel, are on older women (to me that is 75 and older) who have history of multiple pregs. I wonder how clinically significant these are when they get transfused on negative crossmatches. At some point I guess we just have to say, "we have done as much (within reason) as we can to make this transfusion safe " and pray HE will take care of the rest.

Under such circumstances, the only thing you can do is give cross-match compatible blood, although, I must admit that I wouldn't do so much work on such an antibody in the first place.

[lacs]

Our Ref lab uses 3 # media. After running enough tests and if we determine if it's not significant, we back away from the most sensitive method. If everything is ruled out but specificity can't be determined, we send xm compatible units, using (usually) most sensitive method.

[David Saikin]

When we have ruled out "all" the usual suspects but still have some weak, unresolved reactions, we tranfuse AHG xm compatible. If the reactions are strong we will send out the specimen but otherwise we chalk it up to oversensitivity.

[lacs]

Sounds like we are on the same page as far as sample handling:)

[rebeccarjthomas]

Well, I worked for many years in a Ref Lab that routinely tried to duplicate the method used by the customer. This was a starting point, often reflex testing in PEG. Currently I'm working in a Ref Lab that chooses to use two methods on each sample. Many of our current customers use the ECHO. We are going to be performing manual solid phase panels in an attempt to see if we are missing any thing by tube and/or gel that our customers are picking up. As to Malcolm's comment about the insignificance of something detected only by ECHO - I disagree. Would you not honor an anti-Jka only found in ECHO?

Becky Thomas

[Malcolm Needs ☆]

As to Malcolm's comment about the insignificance of something detected only by ECHO - I disagree. Would you not honor an anti-Jka only found in ECHO?

Becky Thomas

You are completely and utterly right Becky, and I stand corrected. No, I would NOT ignore an anti-Jka in any circumstances.

That having been said though, I have never yet come across a "definite" anti-Jka, sent in by one of our hospitals using one technique, that we have not been able to identify and confirm using one of our many techniques - but I'm not saying that it could not happen.

:imslow::imslow::imslow::imslow::imslow:

[AMcCord]

When we have ruled out "all" the usual suspects but still have some weak, unresolved reactions, we tranfuse AHG xm compatible. If the reactions are strong we will send out the specimen but otherwise we chalk it up to oversensitivity.

That is also our policy. Our reference lab sometimes gives us the same sort of results - the usual suspects ruled out, transfuse AHG xm compatible blood - so I feel our policy is appropriate.

[NatishaDixon]

For our reference samples, we perform a 3 cell screen with an auto control using both LISS and PEG initially for all new patients. If we have negative results with those media, we then use Gel. If necessary, we perform a screen using ficin treated red cells to try to replicate results of the submitting facility. We have seen antibodies demonstrated in Echo that were not detected by PEG method but that is why we include enzyme treatment and Gel testing if a submitting facility has suspicions.

[ijames]

Hi David, I have been reading pathlabtalk for some time, and find the information very helpful. We use gel as the primary method. We have had a case where the gel screening was negative, but the patient had an anti Jka. I have spoken to colleagues at other labs who have similar experiences. There are some instances where the tube method by various potentiators will provide a stronger reaction than the gel method.