I have a patient with a positive DAT (IgG).  She has not had any recent transfusions.  Her antibody ID shows a clear cut anti-E and anti-S.  Is there any compelling reason to do an elution?  I used to work in a reference lab and all positive DATs would have elutions performed, but now that I'm in the hospital and it would be a send-out test for us, I'm questioning the value.  There is a good chance this patient will also move to hospice care soon.

These are just hypothetical questions.

 

How sure are you that this patient hasn't been transfused at another facility? i.e. how reliable is the history information that's been communicated to you?

How likely is the patient to receive a transfusion in the near future?

Our blood bank policy is if there has not been a transfusion in 3 months we would not do the elution.  Granted if you do not have any previous history on the patient you are relying on their word, but its not like you are asking if they took a certain medication that they may or may not remember.  Most patients, will remember if they received a transfusion or not.

 

Now I have some older techs that will still run one to see, and if we have a patient that looks to be a WARM auto we will run one, but in general we don't unless proof of transfusion

 

But there is a small possibility that you have bad intel as goodchild said and you may miss something.  Kind of a judgement call.

At our facility we do not do an Elution unless the patient was transfused within the last 30 days.  If we have reason to believe that the patient is not a reliable historian we will do an elution (like they say they have never ever been transfused but we can see that they have or the nurse indicates they are not of sound mind.)   There is always a risk that the patient did not remember a recent transfusion but we have never had an issue and this mirrors what our reference laboratory does.  

I have a patient with a positive DAT (IgG).  She has not had any recent transfusions.  Her antibody ID shows a clear cut anti-E and anti-S.  Is there any compelling reason to do an elution?  I used to work in a reference lab and all positive DATs would have elutions performed, but now that I'm in the hospital and it would be a send-out test for us, I'm questioning the value.  There is a good chance this patient will also move to hospice care soon.

Do the E and S antigen typing , if it is mix field then do elution.

to add to goodchilds response, I would do an elution just to prove there is nothing else in there. I would also do it now, before another transfusion becomes urgent. Since you don't do eluates on site, you don't want to have this happen at 2 am....

Before I got too involved with testing, I would check out the hospice angle. If the patient/family are still up in the air and the patient's hgb is low, I'd send it out if the patient had been recently transfused or is a poor historian. If the hospice admission is a sure thing, but just hasn't happened yet, I would ask whether or not one last transfusion is likely before the patient status is changed to hospice. If yes, then send it out, as above. Hospice patients aren't going to be transfused (or shouldn't be if the 'rules' are followed) - that's the whole point of hospice...comfort care only. No point in running up a bill if the patient isn't going to be transfused.

Edited October 30, 201410 yr by AMcCord

Thank you for all of the input.  The patient was transferred to hospice care today.  I will keep all of your answers in mind for when this comes up again (since I'm sure it will).  

I was in the reference lab for 10 years (do all you can to get an answer), so I'm still adjusting to the hospital setting (do what is necessary to get safe blood, cost-effectively).  

You might find this article form John Judd to be of interest:

Judd, W.J., et al, The Evaluation of a Positive Direct Antiglobulin Test in Pretransfusion Testing, Transfusion 1980; 20:17-23

 

In this University of Michigan study, an analysis was performed of 879 samples with positive direct antiglobulin tests.  Eluates were performed and 83 were reactive.  Most were autoantibodies and a few contained penicillin/Keflin antibodies and a few contained passively acquired anti-A. 

In only 11 of the 879 cases allo-antibodies were detected in the eluate.  After 14 days allo-antibodies detected in the eluate were also detected in the plasma in all but one patient sample that eluted anti-K 17 days post transfusion. 

 

The article states, "One of the six patients whose red blood cells eluted a transfusion-induced alloantibody, but in whom the eluted antibody was not detected in the serum by routine pretransfusion screening tests, had been transfused 17 days before a detailed serological evaluation of the DAT was performed (case 4, Table 3). The red blood cells from this patient eluted anti-Kell. This isolated instance does not warrant an extension of our definition of “recently transfused” to a post transfusion interval beyond 14 days, for to do so would only increase the number of samples requiring evaluation with very little corresponding gain in terms of significant serological findings." 

 

The University of Michigan established a 14-day cut-off for "recently transfused" when determining if an eluate needs to be performed.  We have chosen 28 days as our "recent transfusion" cutoff to perform an eluate.  If the DAT becomes positive within 28 days we will perform eluate, if greater than 28 days since transfusion we will not perform eluate.  The article was written in 1980 and the automated testing methods for antibody detection widely in use today are likely to be more sensitive than those used in the study.

Oh brother, back to the Eluate question again for me also. Current case: patient with historical Anti K, transfused 2 units of RBCs in October that were K neg only. Then we found an Anti E last month (early November) .   RBC Units were then  screened for both antigens before transfusion last month. Now the patient, in house again today, has a classic Anti K and Anti E in the serum still and has a 2+ DAT on the Echo (solid phase), micro pos DAT in tube, complements neg. The tech doing the workup thinks that the DAT is due to E sensitized red cells from the transfusion in October (assume those units were antigen E pos)  and doesn't think an eluate is worthwhile.

 

So after I  changed our Eluate and DAT procedures to send out an eluate when: a)  recent transfusion (under 3 months)  with a pos DAT or when a Trans RX is suspected, now I am getting push back from a tech. I know lots of people don't bother with eluates after a couple of weeks but I decided to go with the most extended timeframe which is the 3 months. I need consistency here due to the large number of techs who are crosstrained in the BB but aren't in there often enough to have enough experience with such situations. Am I back to square one and maybe need to change the policy to shorten it up to ""pos DAT within 2 weeks, one month???" AARRRGGGG. Thanks 

Karrie - ours says 3 months. if there are transfused red cells there, there is the possiblity I guess...

Thanks Auntie-D. In this case, I can tell that the MD (one of the few here) is questioning a delayed hemolytic transfusion reaction based on all the other tests that were ordered but nothing has been said to the Lab at all - but that's another whole story.

 

I really would like to work out a "do this when this happens" algorithm or at least have some specific statements in the SOPs  for the benefit of the part-timers which is why I am beating this to death. I know that the tech is looking at a couple of 'clean" crossmatches which show him that there are no antigens that the current donor units have that are causing an incompatibility with the patient today but it seems to me that the patient may be developing a new antibody that isn't showing up in the plasma quite yet? It would be great to avoid another delayed hemolytic transfusion reaction if this is the  case.

We only do eluates on an IgG positive DATs if the patient has been transfused in the past 3 months.

This was just the information I was looking for!  We have a current patient who was transfused at our facility for the first time on 10/17.  Her antibody screen was negative and she received one unit.  She returned on 11/1 and had a positive screen, panel (some negative cells), autocontrol and 2+ IgG DAT.  I concluded that she had an Anti-Jka and found antigen negative gel crossmatch compatible units.  I even rechecked her previous sample, which had the negative screen and her IgG DAT was 1+.

We sent it up for elution and it came back with anti-Jka and a positive IgG DAT.  

Was I wrong to think we maybe shouldn't have sent it to the reference lab?  All significant antibodies were ruled out except Jka and the units were compatible.  I'm the only consistent blood banker (days) and everyone else is a little leary of blood bank.  In this case the tech didn't even rule out Jka, Fya or S.  She just stopped with the positive Autocontrol and DAT.

10 hours ago, mollyredone said:

Was I wrong to think we maybe shouldn't have sent it to the reference lab?  All significant antibodies were ruled out except Jka and the units were compatible.  I'm the only consistent blood banker (days) and everyone else is a little leary of blood bank.  In this case the tech didn't even rule out Jka, Fya or S.  She just stopped with the positive Autocontrol and DAT.

With the test results you obtained, I think that you were correct in not sending it to a Reference Laboratory - the people who work there are not magicians, and would just be confirming your findings - expensively!  As long as the units were actually tested and found to be Jk(a-b+), and not just found to be cross-match compatible, you were good to go in my opinion.