I know, I know, microscopic readings-yuck! I am trying to move my little lab away from microscopic readings on everything but have to convince our Pathologist first who has no Blood Bank background. So first I am working on eluates: Bottom line, at what strength of a DAT do you perform an eluate if attempting to find antibodies? I want to change the SOPs here to at least get rid of micro DAT readings leading to eluates.    2+ macro?    Please let me know and dear Malcolm, I already know how you feel about micro readings. I need to present a large number of "macro" only reading opinions to our Pathologist who will then agree to dump the micro readings. Thanks!!

I have something of a follow up question for this thread.

 

For individuals who review other technologist's antibody workups: What criteria would you use to repeat someone's positive or negative DAT that seems questionable and how often do you think you have to do that?

 

What do you do to follow up?

Well Karrieb61, you are correct in knowing my opinion on microscopic reading of ANYTHING to do with blood transfusion (with the obvious exception of a Kleihauer), but, if the DAT is positive, and there has been a transfusion within the last three months (unless the DAT was positive before the transfusion and has not got stronger since the last transfusion), I would perform an eluate - UNLESS, the patient has an auto-antibody, in which case it is a complete and utter waste of time.

 

It sort of depends upon the circumstances - but certainly not every time you have a sample.

Yup, I knew you would say that Malcolm and I should have mentioned the fetal stains, rouleux and all those micro-dependent tests.

 

Goodchild, we rarely get these positive DATs and when we do they are microscopic. I haven't repeated a thing yet but might someday. I want to get rid of micro readings because I know if I repeat them, I will likely call them negative. People love their sticky cells here and lean heavily towards calling sticky cells under the scope as positive readings. 1960s here we are but not for long

I am soooooooooooooooooooooo predictable!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I agree totally with Malcolm.  The decision as to whetehr or not to perform an eluate should not depend on the strength of the DAT but on the reason you were doing the DAT in the first place.  A +/- result after a transfusion - yes.  A 2+ on a non-transfused patient who always has a 2+DAT because he's on some sort of medication that causes this - no.

I'll run an LIS report and see what kind of antibodies we've eluted from samples with 'm+' DATs.

Thanks Goodchild, I appreciate that! I sent out an email to a number of local East Coast hospitals but for some weird reason no one will comment on doing or not doing microscopic readings which is what I need to know.

The question you have to ask yourself is, what could the possible clinical relevance of a  few cells stuck together under the microscope have?  Well again, that depends partly on the reason as to why you're doing the DAT in the first place - but also on the sensitivity of your test.  In the old days (and I'm going back a VERY long time) the reagents and techniques in routine use were less sensitive than those that are available nowadays. Consequently, we checked all our reactions (IAT and DAT) under the microscope.  Mind you, I still maintain that nothing we could not see with the naked (trained) eye was actually of any clinical importance.   If you are checking under the microscope because your technique is a bit 'iffy' to say the least, then the answer is not to carry on checking under the microscope, but upgrade you method/techniques.  Lots of techniques out nowadays are much more objective......

I agree with you completely Galvania which is why I am moving the lab forward away from the scopes. My old boss, a Trans Med specialist told me back about 15 years ago that if it's not visible with the naked eye, it is insignificant. I have to convince our Pathologist who has zero background in Blood Banking that the world won't end if we get rid of the scopes for these types of tests. She oversees one other small hospital who borrows procedures from us so she has no opportunity to be exposed to a more 21st century lab. Onward we march!!! 

Last couple of years:

 

20 m+ reactions logged

Eluates:

Panagluttinin: 4 times (1 auto-anti-e spec)

Negative: 12 times (4 were post-transfusion, delayed serological workups)

Not performed: 1 time (complement only, no txns)

anti-Fy^b: 1

anti-Jk^a: 1

anti-C: 1

 

I think Anna's mention of iffy technique is valid.

Thanks Goodchild.  and I agree with everything here in this post. Interesting (to me) to note that you do so many eluates per year. We average one. I'm trying to move them to our local Reference lab.

We have one oncologist who orders DATs on her post trans patients and she is clearly looking for delayed hemolytic reactions based on the chem and heme tests she orders along with it. But once we report out the pos or neg DAT, that's the end of it. In other words, no MD seems to order delayed transfusion work-ups either hemolytic or serologic. I ought to poll people on that one too! For now, I am detailing all of the "investigation" possibilities in our Transfusion Reaction procedure and will include 'at the request of the MD who suspects......." Hope it isn't overkill?

We include an autocontrol with all of our antibody ID panels. If the autocontrol is positive we'll automatically do a DAT. If the DAT is positive then based on a couple of history factors we'll automatically perform an elution.

I'm sorry Karrieb61, but I don't think that your oncologist is worth her salt if she orders DAT's on her post-transfusion patients in the hope that she "picks up" a transfusion reaction on heme and chemistry results.  She sounds like she is looking for excuses for their results!

 

A delayed transfusion reaction is a diagnosis that should be made on more evidence than heme, chemistry or even blood bank results, in particular the physical symptoms of the patient; not just numbers!!!!!!!!!!!!!!!

 

I would be interested to know just how many of these "delayed haemolytic transfusion reactions" have, a) been proved as such and how many were clinically significant and c) how many were a waste of time and money (sorry, I mean delayed serological reactions) or worse, nothing!

Edited November 14, 201410 yr by Malcolm Needs

Why does the letter bee always get changed to a emoticon?  Does the letter bee mean something obscene in USA English that is quite normal in UK English?

Why does the letter bee always get changed to a emoticon?  Does the letter bee mean something obscene in USA English that is quite normal in UK English?

 

It's 'B' ')' is the shortcut for the emoticon for a smiley with shades - it looks like it?? like '<' and '3' gives a heart.

Edited November 17, 201410 yr by Auntie-D

Happy Monday. To answer Malcolm's question- our Onc who orders all the DATs never gets back to us one way or the other and a delayed serologic or hemolytic reaction is never ordered. Based on the chem and heme tests she always orders at the same time that go directly with a delayed reaction investigation, that was my assumption. But again, never a word from her. Whatever, onward we march

 

 

To reply to goodchild's inquiry about repeating a DAT. We do DAT's on cord blood specimens. If one of my staff reports a positive DAT on a cord blood which types as O pos on an O pos mom, I might be inclined to repeat that.

I have been trying to steer my techs away from microscopic reading of DATs - except in a transfusion reaction work up. Fortunately, I have seasoned techs, mostly, and any question of a positive reaction has an eluate done.

We are a hospital on the east coast, by the way.

Let's not discuss the doctors that order a DAT the day after a transfusion, it gives me a headache!

Liz

Can anyone explain the purpose of ordering a daily DAT on a patient? We seem to get small batches of these occasionally.

Thank you in advance.

A daily DAT????  Maybe on a non-iso group bone marrow transplant, but even then that sounds a bit excessive.  Ignorance on the part of the person requesting this sounds a bit more likely.........

I know that we get duplicate testing ordered here when one hospitalist does not see that another physician has ordered tests, and orders them again.

Good luck with your march, Karrieb61.  Change is hard but you got this!  Keep us posted as you move your staff into the "modern" world of Blood Banking, that is NO microscopic readings

Would you always do an eluate in the following scenario? Mother is group O Pos, antibody screen negative at delivery. Baby is group A Pos (or group B ) DAT positive. Do you have to do an eluate to prove the antibody causing the Positive DAT is maternal anti-A or anti-B and not a rare antibody that wasn`t detected when the mother had her screen done? Or can you just state the DAT is positive probably due to maternal anti-A (or anti-B )

In my hospital we do eluates for all cases like these, and I think we are wasting our time.

Edited December 2, 201410 yr by BoroCliff

I think you are too!

 

If you get anti-A (or anti- in your eluate, it does not mean that there is no antibody there directed against a low prevalence antigen as well.  Proving that is going to be a nightmare, because, if the Mum is group O and the baby is either group A or group B, then you will not be able to test Dad's red cells against Mum's plasma, because there will be an ABO incompatibility, and your panel cells are unlikely to express the absolutely correct low prealence antigen against which Mum may have made an antibody!

 

My advice is to let sleeping dogs lie.  Even if baby needs a top-up, or an exchange (which is disappearingly rare under these circumstances), you would cross-match group O blood against her plasma in such a circumstance (I hope!), and so would detect an incompatible unit (1 in a million chance), and where would it get you?  Nowhere!

 

I'm all for doing necessary testing to the nth degree - but unnecessary tests are a waste of time, reagents and money.

 

RANT OVER!