The Title of this Thread sounds like that new reality show on TV...

Anyway, just wanted to throw out a scenario that recently occurred here for which I am still trying to decide what to do.

A couple of days ago, I received a Type and Screen (and crossmatch) on a patient who is frequently transfused as an outpatient. Her Antibody Screen has been negative 19 times (with many transfusions). Towards the end of April, the Tech. obtained a Positive Antibody Screen and Identified anti-K (1+ in GEL). When reviewing her work-up, everything looked accurate.

So here we are about 11 days later. Given her recent POS Screen, I went ahead and set up a Panel along with the Antibody Screen (and knowing that anti-K is sturdy and certainly would not be gone in 11 days). My Antibody Screen and Panel were clean Negative. Uh oh....

So, I pulled the specimen on which she had identified the anti-K and the Antibody Screen was clean NEG. So then I became concerned that perhaps she had mixed up specimens. She had only performed 3 screens that evening so I repeated the other 2 also; clean NEG.

This Tech. has always been one that concerns me working in the Blood Bank; however, her errors are not usually serologic errors like that. Also, it just doesn't make sense. Had she identified anti-Jka (for example) and it was now NEG (and even the repeat of her screen being NEG), I would not have been surprised; but not K.

So what I am now trying to decide is whether or not to remove the anti-K identification for that patient. I know it is not difficult to find K- blood, but, why leave something if it is not accurate (not to mention the cost of screening units; etc)? Or perhaps there is something that is just not occurring to me about this?

WHAT WOULD YOU ALL DO?

Thanks in advance for your replies...

Brenda Hutson, CLS(ASCP)SBB

Were you able to repeat the test using the exact same bottle of reagent red cells (not just the same batch) that were used when the test, originally, gave a positive result?

One thing I have not done yet is check the Lot numbers of the screening cells and Panel to see if they were the same. But in looking at her panel, still do not see even a hint of anything else the positive cells have in common.

But yes, exact same method.

Brenda

Were you able to repeat the test using the exact same bottle of reagent red cells (not just the same batch) that were used when the test, originally, gave a positive result?

Did she have any indication of RBC destruction for the transfusion she received just before the positive screen? Maybe came back a little sooner then expected.

No, in fact, her last transfusion before this specimen (from 04/25) was 04/11; and she did not even end up getting transfused on 04/25.

Brenda

Did she have any indication of RBC destruction for the transfusion she received just before the positive screen? Maybe came back a little sooner then expected.

Does the patient antigen type K neg? With the recent transfusions you might have to do reticulocyte separation to be sure you were testing her cells and odds are that she would be negative. Maybe not worth the effort but if the pt. is Ag neg and a frequent recipient you could maybe justify giving K neg units in future.

Was the original ID made with 3 or more K+ cells reacting?

Could the tech have had reagent anti-K out for anything while doing the first screen? A drip that contaminated a pipet or fell in a sample tube might be all it took to give a pos screen.

A newly developed anti-K might be IgM and if some transfused K+ cells were still in the original specimen and you don't separate your samples when you store them in the fridge you could have done a little cold adsorption which reduced the titer below the detectable level. I also read somewhere once that if we tested more patients shortly after transfusion we would find more antibodies as more of them are anamnestic than we usually think.

OK, can't grasp any more straws.

It may be worth initiating a policy, if you have not done so already, to save and properly lable all positive Gel Cards for later review; if you use the Gel Card system.

It is probably best to look at the decision to remove or not remove the antibody history in terms of risk. There was evidence, however suspect, that the patient had an anti-K. If you remove the requirement of transfusing K antigen negative blood and by a very unlikely chance the patient had a transfusion reaction due to anti-K (or any harm even remotely attributable to the transfusion), then you have to convincingly explain why this was a safe or better decision for the care of the patient to your hospital QA, administrators and/or lawyers, who may only know one thing about blood-it's red!

Thanks for "the straws!"

We do not perform Retic Separation (I have done it before, but not recently; and do not have a proper tool here to score the microhematocrit tubes). The Reference Lab we use does not have any staff that ever performed that procedure (believe it or not). But even if the patient was K-, from a statistical standpoint, that would not be helpful; it would only be helpful if they were K+.

And yes, the Policy here is that they must have 3 cells that are Positive for the identified antibody (and negative for any other identified antibodies; which is N/A in this situation).

I can check the testing that was performed by everyone that evening to see if anti-K would have been out anywhere; but it would have had to fall into the patient's specimen to cause this given that the Antibody Screen was performed first; then the Panel (and the chances of anti-K contaminating the pipette in 2 different scenarios, seems like a long-shot to me).

The Antibody Screen I performed was only 10 days after the initial identification. Of course they were given K- RBCs once it was identified; but that would have allowed 11 more days for the antibody to "strengthen."

Your idea about the K being IgM seems the most "plausible" (though uncertain).

So, still don't know whether I should remove anti-K from the patient's record. My 27 years of experience has taught me to be extemely cautious in removing antibodies unless it is on a current work-up (and this is a discrepany between a previous specimen and the current; and the previous result itself but 11 days later).

Thanks again Mabel!

Brenda

Does the patient antigen type K neg? With the recent transfusions you might have to do reticulocyte separation to be sure you were testing her cells and odds are that she would be negative. Maybe not worth the effort but if the pt. is Ag neg and a frequent recipient you could maybe justify giving K neg units in future.

Was the original ID made with 3 or more K+ cells reacting?

Could the tech have had reagent anti-K out for anything while doing the first screen? A drip that contaminated a pipet or fell in a sample tube might be all it took to give a pos screen.

A newly developed anti-K might be IgM and if some transfused K+ cells were still in the original specimen and you don't separate your samples when you store them in the fridge you could have done a little cold adsorption which reduced the titer below the detectable level. I also read somewhere once that if we tested more patients shortly after transfusion we would find more antibodies as more of them are anamnestic than we usually think.

OK, can't grasp any more straws.

Yes; did that in another place I worked but that protocol was already set-up by my predecessor so I just left it. Have thought about it a couple of times here.....might be a good time to think about it again.

Thanks,

Brenda

It may be worth initiating a policy, if you have not done so already, to save and properly lable all positive Gel Cards for later review; if you use the Gel Card system.

You are correct; and that is the direction I am leaning. Just wanted to see if there was something I was just not considering.

Brenda

It is probably best to look at the decision to remove or not remove the antibody history in terms of risk. There was evidence, however suspect, that the patient had an anti-K. If you remove the requirement of transfusing K antigen negative blood and by a very unlikely chance the patient had a transfusion reaction due to anti-K (or any harm even remotely attributable to the transfusion), then you have to convincingly explain why this was a safe or better decision for the care of the patient to your hospital QA, administrators and/or lawyers, who may only know one thing about blood-it's red!

I second the suggestion to keep the cards. I have them all kept back, and the weekend techs parafilm them so that they aren't cracked when I see them on Monday. It has lead to quite a few revalations, and one firing. But does answer a lot of questions like these.

Yep...been there done that..

Brenda

I second the suggestion to keep the cards. I have them all kept back, and the weekend techs parafilm them so that they aren't cracked when I see them on Monday. It has lead to quite a few revalations, and one firing. But does answer a lot of questions like these.

"The Antibody Screen I performed was only 10 days after the initial identification. Of course they were given K- RBCs once it was identified; but that would have allowed 11 more days for the antibody to "strengthen."

I have seen an anti-K that was not detectible serologically by many methods, caused a hemolytic reaction that night, appeared serologically a few days later and disappeared immediately never to be seen again. So, maybe your antibody did not "strengthen". However I cannot explain why you can't find it in the original tube unless another specimen was used. What us your patient's diagnosis? I think mine had myelodyspasia.

What a coincidence; same diagnosis!

My experience has been that anti-K is usually very stable and hangs out for awhile. But that is why I posted this; wanted to see if others (like yourself) had different experiences.

Thanks

Brenda

"The Antibody Screen I performed was only 10 days after the initial identification. Of course they were given K- RBCs once it was identified; but that would have allowed 11 more days for the antibody to "strengthen."

I have seen an anti-K that was not detectible serologically by many methods, caused a hemolytic reaction that night, appeared serologically a few days later and disappeared immediately never to be seen again. So, maybe your antibody did not "strengthen". However I cannot explain why you can't find it in the original tube unless another specimen was used. What us your patient's diagnosis? I think mine had myelodyspasia.

I am of the paranoid blood banker variety. I would prefer having to justify the added time and work of continuing to give antigent negitive blood if there was any question of an antibody being present, than to have to justify transfusing antigen positive blood to a RCA board if a reaction occured.

Yep, gotcha...

Brenda

I am of the paranoid blood banker variety. I would prefer having to justify the added time and work of continuing to give antigent negitive blood if there was any question of an antibody being present, than to have to justify transfusing antigen positive blood to a RCA board if a reaction occured.

Brenda, Could there be a question of proper patient identification during phlebotomy? Probably not because she's a frequent patient in your outpatient but could the wrong labels have been stuck on the tube? And it's probably not an issue with a contaminated specimen diluting out a weak antibody but I'd say a situation like this is definitely worth a redraw. I wouldn't take the antibody tag off until I had a chance to test a new specimen from scratch. Good luck with your investigation!

Becky

All good points but the mystery still remains that my repeat of her screen (same specmien) did not yield the same reactions.

Brenda

Brenda, Could there be a question of proper patient identification during phlebotomy? Probably not because she's a frequent patient in your outpatient but could the wrong labels have been stuck on the tube? And it's probably not an issue with a contaminated specimen diluting out a weak antibody but I'd say a situation like this is definitely worth a redraw. I wouldn't take the antibody tag off until I had a chance to test a new specimen from scratch. Good luck with your investigation!

Becky

When you repeated on the specimen that was initially positive, did you try different methods? Grasping at straws here. I assume you use plasma. If you use serum, could it be complement dependent. Do you separate plasma/serum from RBCs before you store? Some people do.

Keep the anti-K on her record, it's easy enough to provide compatible blood.

I agree - it is easy for anti-K, but what if the original tech had identified, say, an anti-e?

Hi Brenda

There are a number of reports in the literature of cross-reacting antibodies of bacterial origin that react with the K antigen. At least one of them describes anti-K in an infant that was about 20 months old with no history of transfusion (I could find the reference if you'd like). I have seen at least one myself in a patient with no transfusion history. The antibody was not stable in the sample over time (we attempted to use the sample for training) and it was IgM. The anti-K was not detectable in a subsequent sample. As for leaving the antibody - its a difficult decision, however transfusing K negative red cells is relatively easy considering the frequency of the antigen - I personally would leave it. Your colleague may not be at fault here and it is quite possible that it was not mis-identified or mis-detected.

Cheers

Pam

You may already have answered this, but how long did you incubate the gel cards? Maybe a 30 minute incubation would be enough to get a weak positive reaction from it? Sometimes things come up and you can't get the cards in the centrifuge right at 15...just a guess?

You may already have answered this, but how long did you incubate the gel cards? Maybe a 30 minute incubation would be enough to get a weak positive reaction from it? Sometimes things come up and you can't get the cards in the centrifuge right at 15...just a guess?

That is an idea! In our lab I know that the evening shift is more likely to let something incubate a bit longer then the day shift because of other stuff going on. I might try to incubate it longer and see what happens.