Working up patients with a Warm Auto Antibody

[msmc]

How do you all deal with patients with warm autoantibodies? We recently had a case where the patient had never been transfused, DAT 3+, and plasma reacted with all panel cells at a 1+ strength in the tube with PeG. Also, in capture reactions were the same. An elution was done and all cells had 4+ reactions. Since the patient had never been transfused, no surgeries, or pregnancies, I was wondering whether an auto absorption is really indicated. Is it safe to say that in this particular case units that are weakly reactive can be issued as least incompatible and no further testing required? If, after the current sample expires, additional transfusions are required and the DAT remains the same or decreases in strength is an auto absorption still indicated? Any thoughts out there?

[Eagle Eye]

How do you know that patient was never transfused? Our patient population keeps moving in near by hospital. I would try doing autoadsorbtion once and if there is no alloantibody present, I would issue best compatible unit.

[janet]

You would only want to auto absorb if the patient was not transfused....if you absorb after transfusion you could be absorbing allo-antibody onto those transfused cells......or am I wrong.

We will send our autoantibodies to our reference lab for autoabsorbtion only if they have not been transfused. We also request a full phenotype. Once you know there are no allo antibodies present you could give 'least incompatible' but after that if first transfusion you wouldn't know if allo antibodies were stimulated because the auto would mask it (unless it was a higher titre than the auto). An auto absorbtion can't be trusted (for my thinking above) so we try to give as close to the patient's phenotype as possible (you'll prevent the patient making an allo antibody or if you've given units not the patient's phenotype and it stimulated an allo antibody you won't be introducing those cells again).

But....when the auto shows specificity (ie; anti-e) some literature thinks antigen negative cells may last longer. Then there's the Rh:negative patient who shows that auto anti-e....you would probably not want to give them Rh:positive blood even though it would be your only chance of giving e negative.

There is a good write up on California Blood Bank Society site (www.cbbsweb.org then search for "auto immune hemolytic anemia", it was the first 'hit' for me).

I also have a good write up I found from Dr. L. Petz "Emergency transfusions guidline for AIHA" ....not sure where I found it but I could e-mail it to you:)

[skopti]

If patient was not transfused , then an autoadsorption can be done. Least incompatible units may need to be trasfused.

[Eagle Eye]

I thinl I was not clear. We would only perform autoadsoption if patient is not recently transfused.

[ANORRIS]

Do you rerquire an authorization from the physician to transfuse "Leat Incompatible" blood?

[PAWHITTECAR]

Yes!! I want to make sure that the physician knows. In my previous position the pathologist approved use of "least incompatible" but here I do not have a full time pathologist on site and the "on call" pathologist does not have a real strong blood bank background so I feel safer making sure the physician ordering the transfusion knows what is going on.

[Mabel Adams]

See the Polls section for a poll on the requirement for Dr. signature/notification in warm autos.

[Liz0316]

If your patient has not been recently (or ever) transfused an auto adsorption can be done. I like to get a baseline adsorption even if the patient has never been transfused. I want to see  negative cells somewhere. So, if your screens, panels and elutions are all positive, and you suspect an auto antibody, I would perform one (or send to reference depending on time of day!) Once established that the patient has no allo antibodies and then is transfused, I look at reactions for the next time they come in. Has it only been a few days? are all reactions even and the same strength? It's always best to get diff adsorptions within 3 months of transfusion, but I also realize that may not always be possible. Sometimes your crossmatches will give you the answer. I have found that a XM using 4 drops of plasma and no enhancement (inc 30 -60 min) will depict a compatible XM. Remember your auto antibodies are far more fragile than the allos. An allo antibody will react (at some strength) especially if incubated at 60 min. However, back to patient safety...do the auto adsorption first, then get diff adsorptions done on a weekly basis. That's what we do - unless it's an extreme emergency of course.