I would like to get this forum's opinion regarding autocontrols and/or DAT. Currently, when we get a positive antibody screen, we then run a panel with an autocontrol. If the autocontrol is then positive, we then do a full DAT (poly, IgG and Comp). If the IgG portion of the DAT is positive, we then perform an eluate if the patient has been transfused in the past 30 days.

We just obtained the Immucor Echo analyzer. We were told the Echo does not do an autocontrol and we would have to do a DAT. We have determined that we could still do the autocontrol and run in as a XM with the patient's cells and plasma or do the DAT as recommended by Immucor.

So, my question to you all is... What do you do and why?

Thank you all for your responses! This forum is invaluable!

I would like to get this forum's opinion regarding autocontrols and/or DAT. Currently, when we get a positive antibody screen, we then run a panel with an autocontrol. If the autocontrol is then positive, we then do a full DAT (poly, IgG and Comp). If the IgG portion of the DAT is positive, we then perform an eluate if the patient has been transfused in the past 30 days.

We do this too.

:)

I would like to get this forum's opinion regarding autocontrols and/or DAT. Currently, when we get a positive antibody screen, we then run a panel with an autocontrol. If the autocontrol is then positive, we then do a full DAT (poly, IgG and Comp). If the IgG portion of the DAT is positive, we then perform an eluate if the patient has been transfused in the past 30 days.

We just obtained the Immucor Echo analyzer. We were told the Echo does not do an autocontrol and we would have to do a DAT. We have determined that we could still do the autocontrol and run in as a XM with the patient's cells and plasma or do the DAT as recommended by Immucor.

So, my question to you all is... What do you do and why?

Thank you all for your responses! This forum is invaluable!

I don't have a difinitive answer to your question but I do have experience working in two different Blood Banks one of which recommended no auto control and frounded upon it's very mention, and the other that seemed to not be able to live without the auto-control. The BB that didn't want to run the auto control regularly states that they do not want to open up a can of clinically insignificant warms where as the other BB said that they want to know everything. Both are viable opperating BB's each with a different outlook on auto controls. I hope this helps a little! :)

I think the choice is strictly up to you. Personally, I prefer doing the Direct Antiglobulin Test (DAT) on the patient's red cells (via tube technique.) It's quicker, and it definitely tells me whether or not I need to do an elution. (ie: If I did an auto control and the results were Positive, I would then need to do the DAT.......So I would just as soon do the DAT to begin with.)

The Technical Manual, 16th ed, page 473 states that the "auto control is an important part of the antibody ID. The autocontrol is not the same as a DAT."

Coincidentally, I had just looked this up because we are considering purchasing a Tango, and I found out that it also does not do an autocontrol, so they suggested doing a DAT on each patient (when performing a panel) or just do the autocontrol manually. Some Tango users run the panel on the instrument, then will only do the DAT or autocontrol if all cells are positive. Interesting...

It's not a reg, so I guess this is based on each of our own comfort levels. I've always depended on the autocontrol to tell me auto- vs allo-antibody, but maybe I'm just a creature of habit.

Anybody else out there that does not do an autocontrol for panels? Do you do DAT instead?

I run an auto control only when I am doing an abid. Used to perform it with all screens but stopped when changed to the "newer" technologies. It is an essential with id's, not so much with screens.

I run an auto control only when I am doing an abid. Used to perform it with all screens but stopped when changed to the "newer" technologies. It is an essential with id's, not so much with screens.

I would go as far as to say that it is a total waste of time, reagents and money to perform it with each screen. On the other hand, I think it is essential to run it with each identification panel.

That having been said, I also think a DAT is essential with all identification panels.

The DAT is NOT the same as an auto.

:D:D:D:D

We run an auto control and a DAT with each antibody identification. We use gel for antibody screens and antibody panels.

If you use gel and get a positive auto control with a panel but the DAT is negative...do you do an eluate if the patient has been recently transfused? We recently detected anti-Jk(a) and anti-Fy( (two different patients) by doing an eluate on gel auto control positive, DAT negative cells. I should mention that the DAT was tube method, not gel. Perhaps we should do a gel DAT first.

I'm afraid we've gone down the instrument road and traded the auto control for a DAT when we run the ABID on the instrument. If we run a tube panel, we still do the auto control. I kind of wonder about the usefulness of a tube auto control when run seperately from the panel done by solid phase or gel... Wasn't the original intent of the auto control to run the patient cells under the same conditions as the reagent cells?

As for if the auto control or polyspecific DAT is positive, we do the same as others here.

I'm afraid we've gone down the instrument road and traded the auto control for a DAT when we run the ABID on the instrument. If we run a tube panel, we still do the auto control.

I don't think I explained myself very well in my earlier post. We do as adiescast explained in her post quoted above.

Wasn't the original intent of the auto control to run the patient cells under the same conditions as the reagent cells?

.

I'm afraid so.

It could be worthwhile everybody reading a short paper that came out in 2006;

Sachs UJH, Roder L, Santoso S, Bein G. Does a negative direct antiglobulin test exclude warm autoimmune haemolytic anaemia? A prospective study of 504 cases. Brit J Haemat 2006; 132: 655-656.

This paper not only talks about patients with WAIHA with a negative DAT, but also quotes patients who had produced alloantibodies post-transfusion, where there was a negative DAT, but specific antibody could be eluted from the red cells.

:confused::confused:

We recently had a patient who was transfused 10 days previous, had a negative antibody screen at that point. The next sample had two antibodies and a negative direct Coombs test, but the patient was back because their hemoglobin dropped with no evidence of bleeding. I had the tech work it up as a possible delayed transfusion reaction. The units we transfused were positive for the antigens, but the post transfusion sample was not. My pathologist doesn't want to call it a delayed reaction, but I think she is wrong.

We recently had a patient who was transfused 10 days previous, had a negative antibody screen at that point. The next sample had two antibodies and a negative direct Coombs test, but the patient was back because their hemoglobin dropped with no evidence of bleeding. I had the tech work it up as a possible delayed transfusion reaction. The units we transfused were positive for the antigens, but the post transfusion sample was not. My pathologist doesn't want to call it a delayed reaction, but I think she is wrong.

So do I!!!!!!!!!!!!!!!!

Where does he/she think that the transfused red cells had gone?

An eluation would have been interesting, even with the DAT being negative and the antigens being apparently negative.

:eek::eek:

I agree, too. I wonder if the pathologist offered any explanation of why she thought this scenario was not a classic delayed hemolytic transfusion reaction??

I haven't had a sit down talk with her yet, so I don't know her reasoning. I plan to do that tomorrow when she returns from vacation. Maybe her brain cells will reset by then...she's usually pretty good with these things!

It may be helpful to have a copy of the CDC Hemovigilance Case Definitions attached here handy for your discussion--Although I strongly disagree with their criteria requring a positive DAT for a definitive diagnosis. According to their guidelines, the classic textbook example of an immediate, acute hemolytic reaction and complete destruction of the transfused cells following transfusion of a group A unit to a group O patient would only be a "probable" acute hemolytic reaction!!!

hemovigProtocolTransRxn.pdf

We just recently switched from gel to Echo at our facility and our routine practice is to run a DAT (IgG, C3b and autocontrol) in tube and then confirm the IgG portion on the Echo.

We had a debate when we were still routinely using gel about running an autocontrol or DAT (IgG). We ended up using the MTS IgG card for the DAT (IgG) confirmation of our tube method after we had missed a few very weak IgG reactions in tube only method. My confusion regarding the idea of an autocontrol in gel is that it seems like it is just an autocontrol of your patient in that method vs. a strict autocontrol in tube method. If your using the MTS IgG card the Anti-IgG could be trapping IgG from the patient's plasma or coating the cells....??

We use the Echo and don't run an autocontrol (we don't keep the correct strips for that), instead we run a DAT in tube. We also maintain Gel as a back up (and can run an autocontrol with gel if needed.).

There have been times when we had reactions on the Echo that appeared to be a "solid phase" antibody pan agglutinin/ autoantibody (no reactions in tube or gel) and I wish we could have run an autocontrol on the Echo. These are rare, so in general we don't miss the autocontrol on the Echo.

I wonder why the Echo will not do an Auto control?

A DAT is looking for in-vitro antibody binding and an auto is a cl,assic IAT looking for in-vivo binding. It is not uncommon for negative DAT cells to have a positive auto control and this is commonly due to the LISS effecting antibody uptake (as it is designed to do). If you see pan agglutination in your ID panel, what do you do then? May be the Echo thinks you will switch to alternative technology. I think in these cases most experienced Immunohaematologists will go straight to tube technique and set up an auto anyway.

I wonder why the Echo will not do an Auto control?

A DAT is looking for in-vitro antibody binding and an auto is a cl,assic IAT looking for in-vivo binding. It is not uncommon for negative DAT cells to have a positive auto control and this is commonly due to the LISS effecting antibody uptake (as it is designed to do). If you see pan agglutination in your ID panel, what do you do then? May be the Echo thinks you will switch to alternative technology. I think in these cases most experienced Immunohaematologists will go straight to tube technique and set up an auto anyway.

Hey TimOz,

I am not sure that I agree with your statement about the DAT test looking for in-vitro antibody binding. The DAT has the capability of detecting rbc surface bound IgG antibodies and/or the C3b or d bound product of the complement cascade depending on which reagent(s) are being used. When IgG reagent is used it specifically binds to the Fc part of the in-vivo bound IgG antibody. The auto control can detect anything in-vivo bound to the rbc's including IgM class antibodies whose specific would be detected through the eluate and panel cells, the same as IgG bound antibodies. If I have miss understood you please specify.:)

You can run an auto control on the Echo, we just don't keep the kind of reagent strips that are needed for the testing (our choice.)