Gel and warm autos

[GWBush]

We have recently began using gel and have an increased amount of warm autos. We still use tube (LISS) testing as a back up method. We have recently got a patient that reacted positive (3+) on all cells including the AC. The tube (LISS) panel was negative except the AC. The DAT was positive IgG 3+ and neg c3bc3d. The tube AHG crossmatches were compatible and the patient has not received any recent transfusions. Would you call this a warm auto ab and forgo the expensive workup or is GW too flippant about calling a warm auto?

[adiescast]

We see this with solid phase as well. I have a policy that says when the solid phase panel is the same strength in all the reaction wells and the auto control, but the tube screen is negative, we call it a warm auto antibody by solid phase only (WASP for short). The risk, of course, is that it is remotely possible that the patient has an antibody to a high frequency antigen and something else that is causing the auto control to be positive (or worse, they have been transfused and the positive auto control is due to the antibody to high frequency antigen).

[David Saikin]

Sounds like a warm auto to me. Gel is so sensitive. We have found the same type of reactivity. I guess you (and your Medical Director) have to determine how you are going to handle these. I have never been able to autoabsorb out an autoab using gel. I switch to PeG and perform PeG autoabsorptions - usually can absorb out the auto with one procedure. Then, all workups are in tubes. You also may want to consider how to deal with anti-M, as this antibody seems to show up more frequently in gel (slightly acidic environment).

[Malcolm Needs ☆]

We have recently began using gel and have an increased amount of warm autos. We still use tube (LISS) testing as a back up method. We have recently got a patient that reacted positive (3+) on all cells including the AC. The tube (LISS) panel was negative except the AC. The DAT was positive IgG 3+ and neg c3bc3d. The tube AHG crossmatches were compatible and the patient has not received any recent transfusions. Would you call this a warm auto ab and forgo the expensive workup or is GW too flippant about calling a warm auto?

I would have no problem calling this an auto-antibody.

Not only do we call this an auto-antibody in my own Reference Laboratory, but this is also written into the National SOP used by the NHSBT in the UK.

So far, we haven't killed any patients because of this!!!!!!!

:)

[Antrita]

We also have been getting more warm autoantibody results in gel. We have started looking at automation and I'm leaning towards the ECHO. I never thought I would want to quit gel but I am really tired of working up nothing. I have immucor tube screening cells. When I have weird reactions in gel I make gel dilutions of the immcur screening cells first. If the antibody screen is negative on these (which is about 70%) I leave it at that.

Antrita

[L106]

Antrita -

We have an Echo (and use tube technique with PeG as our "back-up" method.) I thought I would mention to you that in our experience, the Echo does pick up more Warm Auto-Antibodies than what we see with tube technique. Not a lot more, but it does seem that the Echo is a little more sensitive with warm autos.

[Malcolm Needs ☆]

Antrita -

We have an Echo (and use tube technique with PeG as our "back-up" method.) I thought I would mention to you that in our experience, the Echo does pick up more Warm Auto-Antibodies than what we see with tube technique. Not a lot more, but it does seem that the Echo is a little more sensitive with warm autos.

I would agree with that.

I don't use an ECHO, but many of the hospitals that refer to us do, and we have seen a steep increase in such referrals since these machines have been introduced.

[adiescast]

It really isn't the instruments, it's the methods. Both gel and solid phase are FAR more likely to detect a warm auto antibody than tube. I have not compared them to PEG, so I can't comment there. We can sometimes knock out the warm auto antibody by not adding the potentiator (LISS) to the solid phase on a manual run, but we usually just drop back to the tube until the warm auto antibody settles down.

[Malcolm Needs ☆]

It really isn't the instruments, it's the methods. Both gel and solid phase are FAR more likely to detect a warm auto antibody than tube. I have not compared them to PEG, so I can't comment there. We can sometimes knock out the warm auto antibody by not adding the potentiator (LISS) to the solid phase on a manual run, but we usually just drop back to the tube until the warm auto antibody settles down.

Yes, sorry, I meant the method.

:redface:

[Antrita]

I am questioning the validity of the warm autoantibodies we are seeing in the Gel. When you get 2+ reactions in the screening cells and no reactions or reactions where everything is eliminated in the antibody Id panel over and over, I think there is something wrong with the Ortho screening cells. I have one tech that goes immediately to a tube crossmatch when she gets anything in gel, which pretty much defeats using gel at all. This problem use to be in an occasional lot but know it seems to be the oposite, an occasional lot doesn't have problems.

Antrita

[janet]

As some other gel users stated, we too 'drop down in sensitivity' to saline tube IAT with warm autos to see if we can get a negative screen .... or an allo antibody. We have a couple regular users who react with everything in gel, one has an Anti-e and the other an Anti-E .... my understanding is that the allo antibody is usually a much higher titre than the auto antibody (our reference lab even goes on to do dilutions when the 'neat' antibody screen is still reacting with everything by saline IAT.)

[Malcolm Needs ☆]

our reference lab even goes on to do dilutions when the 'neat' antibody screen is still reacting with everything by saline IAT.

Pretty dangerous if the alloantibody happens to be an anti-Jka!!!!!!!!!!!!!!

No, alloantibodies do NOT always have a higher titre than the auto-antibody. Many of our "regulars" with wAIHA have alloantibodies that are no longer detectable, but I certainly would give them nothing but antigen negative blood.

:(

[janet]

Thank-you Malcolm - I thought it was risky practice too ... but that's what they do.

I believe it was a talk by Garratty that stated allo-titres were higher than auto's so I guess our reference lab isn't alone in the dilution step!?!

[lburk]

We only call it a "warm auto" if the eluate is positive with all cells and we are confident it is not an antibody to a high incidence antigen in a recently transfused patient.

[GinaL]

Thank-you Malcolm - I thought it was risky practice too ... but that's what they do.

I believe it was a talk by Garratty that stated allo-titres were higher than auto's so I guess our reference lab isn't alone in the dilution step!?!

Continuing on this thread, both column agglutination (eg, gel) and solid phase methods are more sensitive for detecting warm autoantibodies, just as PEG and enzyme methods. Repeating the test by tube with LISS or even saline suspended RBCs is an acceptable and often used approach. But I do need to comment on the dilution approach to detect alloantibodies underlying warm autoantibodies. We (Dr. Garratty and myself) reported on the comparison of adsorbing autoantibodies with ZZAP-treated RBCs, adsorbing in the presence of PEG, and the dilution technique in Transfusion 1999;39:11-16. The New York Blood Center had previously reported using a 1 in 5 dilution of patient's serum to detect alloantibodies underlying autoantibodies. With the volume of warm autoantibody workups that our reference lab performs, we had wanted to see if we could similarly reduce turn around time on these cases. The bottom line is that 27 of 119 sera with alloantibodies (plus autoantibodies) did not react by tube test with LISS-suspended RBCs after diluting 1 in 5. In other words, we would have missed these potentially clinically significant anitobides. Our caveat, however, is that if adsorptions are not possible (eg, insufficient time prior to transfusion) that dilution is better than just giving least incompatible units. It is established that warm autoantibodies plus alloantibodies do not necessarily react more stronly than warm autoantibody alone, even for 1+ reactivity of the auto. Also, a retrospective adsorption under these circumstances could be used to ensure alloantibodies were not missed by the dilution method. I do have to add that these were the results in our hands; another laboratory may have established their own criteria and approach.

The dilution technique described by Petz and Garratty did not have a predetermined dilution, eg 1 in 5, as used in the NYBC method. Rather, a titration of the patient's sample was performed against a pool of screening RBCs and the dilution where the serum reacted 1+ in the IAT against the pool was selected for testing agianst a panel of RBCs. In the 1980 edition of their text they stated that this method is efficient when (my emphasis/underline) the alloantibody is of higher titer than the autoantibody, but it cannot be used to confidently exldue the presence of alloantibody.

Gina Leger

[Malcolm Needs ☆]

Continuing on this thread, both column agglutination (eg, gel) and solid phase methods are more sensitive for detecting warm autoantibodies, just as PEG and enzyme methods. Repeating the test by tube with LISS or even saline suspended RBCs is an acceptable and often used approach. But I do need to comment on the dilution approach to detect alloantibodies underlying warm autoantibodies. We (Dr. Garratty and myself) reported on the comparison of adsorbing autoantibodies with ZZAP-treated RBCs, adsorbing in the presence of PEG, and the dilution technique in Transfusion 1999;39:11-16. The New York Blood Center had previously reported using a 1 in 5 dilution of patient's serum to detect alloantibodies underlying autoantibodies. With the volume of warm autoantibody workups that our reference lab performs, we had wanted to see if we could similarly reduce turn around time on these cases. The bottom line is that 27 of 119 sera with alloantibodies (plus autoantibodies) did not react by tube test with LISS-suspended RBCs after diluting 1 in 5. In other words, we would have missed these potentially clinically significant anitobides. Our caveat, however, is that if adsorptions are not possible (eg, insufficient time prior to transfusion) that dilution is better than just giving least incompatible units. It is established that warm autoantibodies plus alloantibodies do not necessarily react more stronly than warm autoantibody alone, even for 1+ reactivity of the auto. Also, a retrospective adsorption under these circumstances could be used to ensure alloantibodies were not missed by the dilution method. I do have to add that these were the results in our hands; another laboratory may have established their own criteria and approach.

The dilution technique described by Petz and Garratty did not have a predetermined dilution, eg 1 in 5, as used in the NYBC method. Rather, a titration of the patient's sample was performed against a pool of screening RBCs and the dilution where the serum reacted 1+ in the IAT against the pool was selected for testing agianst a panel of RBCs. In the 1980 edition of their text they stated that this method is efficient when (my emphasis/underline) the alloantibody is of higher titer than the autoantibody, but it cannot be used to confidently exldue the presence of alloantibody.

Gina Leger

Thanks Gina; that is a really useful post.

If you are still working with George, please give him my very best wishes and wish him a Merry Christmas and a Happy New Year from me.

:D:D:D:D:D