Incompatible with negative antibody screen

[Desoki]

Dear friends;

Today I faced a problem during trying to issue blood; we received EDTA blood sample of patient suffered from CVA, we did antibody screen result was negative and pt grouped O positive we tried with 3 units immediate spine only one unit was compatible and others were incompatible, we repeated antibody screen result also was negative for the second time, we did gel AHG for these two incompatible units the result one +2 and other was very very weak positive, we changed our lot number gel card but the results were same, we did DAT for these two incompatible units but result was negative.

My possible cause may be due to drug, what is your explanation and also may I issue least incompatible unit if don’t find any compatible?

Thanks

[Malcolm Needs ☆]

I wouldn't be at all surprised to find that your mystery antibody is an anti-M and, if so, least compatible blood would be quite safe.

[JOANBALONE]

Anti-M would be my first guess too.

[Desoki]

I wouldn't be at all surprised to find that your mystery antibody is an anti-M and, if so, least compatible blood would be quite safe.

why you suggest anti M

[Desoki]

Anti-M would be my first guess too.

why anti M

[Malcolm Needs ☆]

Well, the thing is that anti-M is one of those antibodies whose reaction depends very much on the conditions of the way the tests are incubated.

It has the "ability" (for want of a better way of putting it) to sensitise red cells very quickly at "room temperature", and once it has sensitised the red cells can cause agglutination, but putting the tests at 37oC for a (comparatively) short time does not give it time to "elute" back off. In addition, gel column technology uses a slightly lower pH than would normally be used in other technologies, and anti-M is well known to react at lower pH's than other specificities.

All that having been said, this is still something of a "guess", rather than a definitive answer!

[Eagle Eye]

I am assuming you are using Gel for your TS. We do see this with anti-Lea &/or anti-M....which is reacting at low temperature so you will not pick up while doing screening because of 37C incubation.

[Steven Jeff]

I am right in thinking that when using gel technology for antibody screening that you will pick up Anti-M irrespective of whether they are mainly active at 4 or 37°C, that is my experience. I have to refer on to a reference laboratory (Malcolm’s) for the thermal amplitude of the antibody who has to use LISS tubes for that purpose.

Msdesoki can you clarify what is your routine technology for antibody screening please

Regards

Steve

:confused:

Edited April 16, 2011 by Steven Jeff
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[rravkin@aol.com]

Msdesoki,

If you perform your antibody screening with tube method using LISS then take readings at all phases of testing you may be able to confirm Anti-M especially when your Gel card screening is negative.

[khalidm3]

THANKS FOR COOPERATION , we use three screening cell by gel AHG technique and EDTA pt sample

[Desoki]

me and khalidm3 work in the same place, we use three screening cell by gel AHG technique and EDTA pt sample

[Desoki]

Well, the thing is that anti-M is one of those antibodies whose reaction depends very much on the conditions of the way the tests are incubated.

It has the "ability" (for want of a better way of putting it) to sensitise red cells very quickly at "room temperature", and once it has sensitised the red cells can cause agglutination, but putting the tests at 37oC for a (comparatively) short time does not give it time to "elute" back off. In addition, gel column technology uses a slightly lower pH than would normally be used in other technologies, and anti-M is well known to react at lower pH's than other specificities.

All that having been said, this is still something of a "guess", rather than a definitive answer!

Today I resumed working in that case, I did DAT and autocontrol test, antibody identification for that patient the result was positive autocontrol, positive DAT and negative reaction with all 11 cells in Ab identification, then I did acid elution test for pt sample and Ab identification for that elute, the was very strange it gave definitely mixed field reaction with all 11 cells, I repeated it but the result was same. What is your opinion?:mad:

[JOANBALONE]

Did your antibody id include room temperature incubation?

[khalidm3]

Today I resumed working in that case, I did DAT and autocontrol test, antibody identification for that patient the result was positive autocontrol, positive DAT and negative reaction with all 11 cells in Ab identification, then I did acid elution test for pt sample and Ab identification for that elute, the was very strange it gave definitely mixed field reaction with all 11 cells, I repeated it but the result was same. What is your opinion?:mad:

Mostly Improper technique or defective reagents

[Malcolm Needs ☆]

Sounds like it could be an auto that is mostly on the patient's red cells, but not free in the plasma.

[Yanxia]

Today I resumed working in that case, I did DAT and autocontrol test, antibody identification for that patient the result was positive autocontrol, positive DAT and negative reaction with all 11 cells in Ab identification, then I did acid elution test for pt sample and Ab identification for that elute, the was very strange it gave definitely mixed field reaction with all 11 cells, I repeated it but the result was same. What is your opinion?:mad:

As to the mixed field I don't know what is your technique, if it is gel AHG as you used before, I think it is maybe because cold antibodies, when the card is spin, the temperatue is lower than the previous incubation , part of the cells is sensitived, so the cold antibodies can give the mixed field result.

Edited April 18, 2011 by shily

[JOANBALONE]

I have also seen mixed field in gel eluate testing when patient has warm autoantibodies.

[Yanxia]

I have also seen mixed field in gel eluate testing when patient has warm autoantibodies.

I am very intersting in it, and why?

[JOANBALONE]

I have no idea

[Townsend]

Sounds like you could have a cold autoantibody. You could try a tube screen with cold (4 degree) incubation. We generally refer to these as "cold autoantibodies" if they react only at the 4 degrees and other antibodies are ruled out in gel (i.e. your negative panel).

What did the extended (tube or gel) crossmatch look like?

Stephanie Townsend, MT(ASCP)SBB

[Yanxia]

Today I resumed working in that case, I did DAT and autocontrol test, antibody identification for that patient the result was positive autocontrol, positive DAT and negative reaction with all 11 cells in Ab identification, then I did acid elution test for pt sample and Ab identification for that elute, the was very strange it gave definitely mixed field reaction with all 11 cells, I repeated it but the result was same. What is your opinion?:mad:

msdesoki, if you find something new for this antibody?

I reread your post and find a question, why this antibody(antibodies) in plama react with donor cells and not with screening cells? From your elution test we know this antibody react with panel cells, I think if the patient plasma not react with panel cells too, then we can get a conclusion this antibody react with some antigen will decrease quick on cells, because the screening cells will be older than donor cells routinly( JUST a guess). And the antibody in the elution is stronger than in plasma.

[profbaud]

Other Possibilities:

1. Any transfusion history available? DAT results? Perhaps you have a low frequency antibody that you are missing in your screen and have picked up in the crossmatch. Also a strong cold agglutinin may be missed on the screen if you are using the Provue since the cards are preheated, but if you do the crossmatch in manual gel, it will be incompatible.

[Thandar Aye-zheng]

New Blood Banker here. Please bare with me if I am not making sense.

I am thinking panagglutinin on eluate with non-specific cold. Try 4C incubation with pt's serum on the panel and prewarm crossmatch with these 2 incompatible units? see if the panel turned up pos and prewarm xm turn up comp? ?

[sdweaver29]

I have a similar issue. Gel antibody screen negative, therefore an immediate spin crossmatch done but all units attempted were incomaptible 2+. Carried to 37 and reactions are still present, although weaker. Now negative at coombs. Short cold shows positive for cold agglutinin. If my REST adsorption is negative screen at 4C, where does that leave me with the crossmatch. The original crossmatch shows incompatible at 37 which I consider significant. Is it acceptable to report as incompatible due to cold rather than prewarm crossmatch and then report compatible.

I really have a hard time just reporting compatible after prewarm technique. The evening staff is all generalist and they are too quick to jump on prewarm technique without investigating the cause of the reactions.

Does any one have a good flow chart for working with cold and the best approach to handle the crossmatch and reporting? I would greatly appreciate any help here from those blood bankers that have more experience.

[adenbashir]

It's possible cold reacting antibodies, but the best way to reslove this type of problems is to switch computer crossmatch as long as you can validate EXM eligibility.