Pretransfusion DAT

[Sue Miller]

We currently perform a DAT on any patient who has a type and screen or type and crossmatch and has been transfused within the last 3 months to identify delayed transfusion reactions. I would like to discontinue this practice. What does everyone think of this practice?

[Mary**]

:tongue:We have never done that if the antibody screen is negative. We do include an autocontrol with antibody identififications.

[David Saikin]

We used to do an auto control with our antibody screen, but when we switched to gel we dropped that. We do perform one if we do an identification. More than a few years ago (late 1980's) it became fashionable as a cost-saving measure to drop the routinely run auto ct. Many small (and medium) institutions kept it for just the reason you still do it. It is not a regulatory requirement . . . but it does let some medical directors sleep better. It is not the standard of care, but you should call around in your locale just to see what your peers are doing.

[John C. Staley]

Give up the practice and join us in the 21st century.

We dropped routine autocontrols over 10 years ago. One argument you could use would be: when was the last time you had a positive DAT that was due to a delayed transfusion reaction and the antibody screen was negative and how many have there been in the past 10 years or so?

Also, we always perform either an autocontrol or DAT with antibody ID. If there is a delayed transfusion rxn well pick it up then.

[AMcCord]

I vote with John. We dropped routine auto controls when we switched to gel years ago. DATs only with antibody IDs or reaction workups.

[Max001]

I agree with John also. Too often BB-ers are reluctant to give up the 'belt and suspenders' but it's understandable. Our 'extra-careful' natures are often the only thing that stands between a patient and a problem.

In fact you could make a case for dropping the IS and the albumin phase of reading on tube testing. You still incubate, you just don't read it.

Has everyone turned to Gel testing? It was becoming the norm when I left the field in 2002, but we still did some tube testing, some antibody panels, routine T&S.

Just curious.

[ckcheng]

I agree with all of you that perform autocontrol during pretransfusion testing should be discourage. Perform autocontrol only when you do antibody workup, when autocontrol is positive, do DAT to see if it is due to the testing media.

CK Cheng, MSc, SBB(ASCP), CQA(ASQ)

Hong Kong

Dec 3, 2008

[porterl]

We do not routinely do DATs on any patients, unless we are doing an antibody identification. No reason to suspect a delayed hemolytic transfusion reaction, if your antibody screen in negative.

[adiescast]

We do a DAT or auto control with panels (we do the DAT if the panel is done by solid phase, auto if done by tube). We do DATs on cord blood workups. If we get a transfusion reaction post DAT reactive, we test the pre-DAT to see if it was reactive. That's pretty much it unless a doctor orders a stand alone DAT.

[Kathleen BBSuper]

Question anyone...if you have a positive auto control do you automatically perform a DAT? What if the auto is consistently positive...DAT every specimen? How often would anyone proceed to an eluate based on a positive DAT result? Does everyone use the 3 month rule?

[Eagle Eye]

1) we do not run autocontrol/do DAT as our pretransfusion test. We run AC with our antibody identification if antibody screening is positive.

2) If Autocontrol is positive, we do DAT and if DAT is positive we do an elution. Many times we see AC positive and DAT negative.

3) We do DAT on post specimen as part of our reaction workup and if post DAT is positive then we do DAT on pre sepcimen.

[Kathleen BBSuper]

So does everyone automatically perform an eluate on a positive DAT...on all patients...on only those recently transfused...and how recent is recently transfused? Previously we had the previous 3 months as recent transfusion, but since the majority of antibodies are present in plasma by 20 days post transfusion and most of our eluates were negative or panagglutinins, we opted to proceed to a 30 day rule. Please share current procedures.

[Joanne P. Scannell]

We perform a DAT as routine with all our Pretranfusion Type and Screens. And it is our policy to inform the physician (documented).

There are basically two reasons, not just one that is mentioned in here.

1. As stated, it will detect post-transfusion positive DAT due to a DHTR ... either by going from negative to positive or by increasing in grade.

2. It also provides additional information to the physician ... perhaps even set him/her in a different direction regarding diagnosis and treatment. We have had many transfusions cancelled because the physician did not know the patient had a positive DAT and when informed, chose another avenue besides transfusion, eg. medication.

As far as do we do the 'workup'? If the patient has been transfused in the past 3 months (looking to change that to perhaps 6 weeks), we will perform an elution.

[Trek Tech]

We would only repeat the elution if the autocontrol was stronger than the previous one (within that 30 day period).