Advice needed please!

[CarolS]

I have a question for all of you blood bank gurus out there and I apologize if this topic has already been discussed..... we currently do auto controls on all patients who have been recently transfused (within the past 30 days), then DAT and elution if positive. Many of our patients are regularly transfused, so therefore have autos done with each screen. Many of them have positive DATs, so we are ending up doing many, many elutions. I can't remember how long it's been since we eluted a clinically significant antibody..... maybe 3 years. What are the recommendations for when auto controls, DATs, and elutions be done? I feel like we are just spinning our wheels!

Thank you in advance!

[AMcCord]

There is no requirement to perform an autocontrol or DAT with a crossmatch. We only do them if we are doing an antibody ID (usually start with an auto) or suspect a transfusion reaction or if a physician specifically orders a DAT.

[Bill]

Like AMcCord, we only do autocontrol with Antibody ID, only do DAT with positive autocontrol. We are small hospital with 165 beds.

[khalidm3]

There is no requirement to perform DAT/Auto Control with Pre transfusion compatibility testing (Antibody screen/cross match), our policies require to perform DAT/Auto Control with Anti body Identification, Neonatal cord blood DAT along with blood group, transfusion reaction investigations and sure if a physician orders for diagnosis.

[David Saikin]

When we did tube testing we always performed an auto ct. Since we have switched to gel, like the others, we only perform and auto when we do an abid. Likewise, if the auto is positive, we then perform a DAT.

[CarolS]

Thank you to everyone who responded. This confirms what I was thinking and I don't know why it took me so long to ask. Old habits do die hard!

Ok.... so then we only really need to do the auto with an antibody ID, then the DAT if the auto is positive. Are there some rules about when it is absolutely necessary to do an elution, or is it done with every positive DAT when the patient has been recently transfused?

Another elution question.... when is it necessary on a cord blood? Currently we do an ABO/Rh and DAT on all newborns from Rh negative moms. Then we do an eluate on all positive DATs... a freeze thaw when we suspect an ABO incompatability, and an acid when we suspect anything other. Is this necessary, or could we only do one if specifically requested by the physician?

Thanks again for all of your help!

[tbostock]

We don't do an elution with every positive DAT; only if indicated (suspection of delayed hemolytic reaction for example), or if requested by the physician.

Same for cord bloods; only if indicated (not an ABO issue, but for example if the mom has a clinically significant antibody, or maybe the possibility of a low incidence antibody in the mom not picked up by a screen) or ordered by the physician.

[Eagle Eye]

we only run AC with ABID and if AC pos then we do DAT & elution. WE only do ABID every seven days unless there is change in pattern for antibody screen.

[Mabel Adams]

We only do elutions if patient was transfused in last 14 days and now has pos DAT.

As for cord elutions, here's my logic: If you find ABO antibodies, you can't prove HDFN is due to ABO since anti-A,B often crosses the placenta of O moms (absence of ABO antibodies could rule it out but that is rare). So you know about as much about ABO HDFN from knowing that mom is O as you do after you do the elution. If you suspect anti-D, you aren't going to be able to tell very well because the mom will have been given antenatal RhIG so there will be anti-D present (which can sometimes cause a pos DAT in the baby). If mom's titer is sky high, you will suspect anti-D HDFN but that information comes from the mom's antibody screen and history, not the eluate. Similarly, if the mom has some other antibody, her antibody screen/ID is the most likely source of useful information. If you test an eluate against screening cells and find nothing you will write if off unless the baby is really ill (not just being screened cuz mom is Rh neg). If the baby has significant HDFN with no other explanation, you may use an eluate to test against Dad's cells or otherwise look for an antibody to a low freq antigen but that is very rare. Doesn't seem to me like you get much benefit from cord eluates unless you have a sick baby and mom has a neg antibody screen or you need to work up a really complex mixture of antibodies or something. The AABB recommendations do not include doing anything but an Rh type (for RhIG determination) for babies showing no signs of HDFN.

[Dr. Pepper]

One may also argue that there are better things to do with your time than work up a positive DAT patient who has a 14 g hemoglobin (unless requested). Eluates and the various procedures for demonstrating drug antibodies can be a lot of work for a patient who's showing no signs of immune hemolysis.

[MAGNUM]

concerning the elutions, we only do the elutions on cords if the mother has a significant antibody.

[Townsend]

As with most of the previous replies, we only do AC with ABID, with pre-transfusion neonatal samples, and of course when ordered by the physician or as part of a transfusion reaction workup.

As for elutions, we perform them on positive DATs if the patient has been transfused within the last month and on all neonatal positive DATs. That does mean a lot of elutions on babies (usually just ABO abs or anti-D from RhIg in the eluate). However, we are a pediatric hospital, so mom's sample is not always available. We do try to contact the birth hospital for BB history on mom, but I can think of more than one case where an incorrect history was given from the birth hospital. (maybe they were looking at the wrong patient, who knows) We have even had hospitals call back later to say "oh, wait, that baby was transfused after all - 6 aliquots of Oneg red cells". (no wonder the Apos baby is now typing Oneg!).

So, to cover our butts, we do the eluate. The antibody eluted is not always what is seen in the baby's plasma (i.e. ABID). The screen could be negative and antibody is only recovered in the eluate, or could be a different combination. (i.e. anti-D in eluate and anti-K and anti-D in plasma) Anyway, we like to see the whole picture when trying to find compatible red cells for a neonatal transfusion, and this helps especially when mom's sample is not available.

[Townsend]

Correction to my previous post..... "As for elutions, we perform them on positive DATs if the patient has been transfused within the last month and on all neonatal positive DATs"...

That is only for positive INPATIENT neonatal DATs (or for pre-transfusion testing). We don't do elutions on all of our outpatient positive neonatal DATs unless specifically requested by the pediatrician. Now THAT would be a lot of elutions!

[MeganPLT]

So I was looking at this thread because I too am looking to see when to do elutions, and like most places we perform eluates on patients who have a positive DAT after performing their ABID but we do the elution regardless of transfusion status to determine if they are warm autos or in cases where a patient was recently transfused to see if a new antibody pops up...but what do you do in cases where a patient has a positive DAT, is a known warm auto - let's say previous elution studies from 1 month ago were pos with all donors tested and adsorption studies showed no underlying alloantibodies, and was recently transfused (1 week ago). Do you do the elution again or do you have a seperate policy for known warm autos and when they need a repeat eluate? Let's even take it a step further - how often do you repeat the adsorption studies?

Edited June 14, 2011 by MeganPLT
added addtional info and question

[epfeiffer]

We only do an autocontrol on Antibody IDs and DATs only on positive Autocontrols, unless requested.

We will do an elution on Patients with a positive DAT that have been transfused in the last 21 days. If a patient has a known warm autoantibody we will do an elution if the strenght of the auto control or DAT increases, or every six months. (We only deal with adult patients) We will also do elutions if requested specifically by a physician.

[rravkin@aol.com]

We perform the eluate under circumstances given; however we specifically run the eluate with screening cells first and if positive proceed to panel. I'm not sure if others do the same but this sequence will save some time and reagents.