DAT question

[lioness@50]

This is my first post! I worked up my first transfusion reaction the other night (2am). Using gel. the pre specimen game me a DAT reation a weak 1+. The post specimen yielded a true negative. "Talk" thru the lab was that we (techs) could overlook a pre positive DAT if the post DAT was negative. I asked my supervisor about this (no SOP) and she said that even though AABB does not recommend that positive pre transfusion DAT's be ignored, she and our pathologist had not only overruled AABB but had decided to not rejoin AABB this year. How do other labs handle the DAT situation, and what do you all think of "jumping ship" concerning AABB? Thanks in advance!

[Lcsmrz]

We don't even perform a Pre-DAT, if the post-DAT is negative. How much you do with a positive DAT depends on the comfort level of the pathologist and the patient population you have.

AABB is an outstanding organization -- one that deserves support and membership! No one has done more over the years for the blood banking community (from donor to recipient to Techologists to technology) than they have, and other agencies look to them for guidance in the Transfusion Medicine arena, including the FDA. Many times, though, it short-sightedly comes down to dollars in the budget ...

One other thing to remember about the AABB is their 20+ year focus on systems, something that other agencies have only recently (and begrudgingly) adopted. They are a progressive voice in the very conservative lab field, and way ahead of everyone else in their view of quality -- indeed, others are following their lead and playing catch-up!

Larry Smrz, MBA, MT(ASCP)SBB, CQA(ASQ)

Indianapolis, IN

AABB Assessor

[Mabel Adams]

AABB does not recommend that positive pre transfusion DAT's be ignored

Where does the AABB say this?

[skopti]

At our facility, We only perform a DAT on the pre-Transfusion sample if the Post transfusion DAT is Positive (+).

IS your facility CAP Accredited?

[Yanxia]

I think the pre-transfusion DAT's meaning is to decide whether the antibodies which have been tested in the serum is auto or allo. And when the minor crossmatch is positive we will test it to look for the reason.

[John C. Staley]

Minor crossmatch????? Please tell me that you are not routinely doing minor crossmatches!

[Yanxia]

My english is not good, perhaps I have not express my meaning correctly.

We do minor crossmatch routinely, and if we see it is not compatible, we will find the reason/s which can result the incompatible in minor crossmatch.Testing DAT is one of the ways we will do.

[johna]

My english is not good, perhaps I have not express my meaning correctly.

We do minor crossmatch routinely, and if we see it is not compatible, we will find the reason/s which can result the incompatible in minor crossmatch.Testing DAT is one of the ways we will do.

Just for your information Shily the minor crossmatch in the United States was eliminated many years ago. It is a waste of time and resources. You may wish to consider dropping it from your routine testing.

[johna]

AABB does not recommend that positive pre transfusion DAT's be ignored!

I'll have to echo Mabel's question on this. I don't think the AABB says anything one way or the other about the need to work up a pre-transfusion DAT. Unless a DAT is suspected of being associated with a hemolytic episode (HDN, transfusion reaction, drug therapy) the information obtained from working one up is generally of little or no interest to anyone.

[Yanxia]

Just for your information Shily the minor crossmatch in the United States was eliminated many years ago. It is a waste of time and resources. You may wish to consider dropping it from your routine testing.

Nice to meet you ,Johna.

In our country we don't screen the donor for irregular antibodies, we do minor crossmatch. And I think if the patient is T active, we can find it through this test.

[Abdulhameed Al-Attas]

you are right if you are NOT screening your Donors for irregular antibodies, then you must do the minor crossmatch.

[GilTphoto]

Something doesn't sound right here. If the pre DAT was positive, how can the post DAT be negative? Because of this discrepancy, I would investigate further. If the patient has been transfused recently, I would do an eluate on both samples and repeat antibody screen with 30-60 minute incubation. If the patient hasn't been transfused recently, the pre DAT was probably drug induced, or a false positive.

[madhu]

Hello! Everyone.

I am usually a 'reader' not a 'poster'. Its interesting to read all exchanges.

I agree with Shily. A lot of countries do not screen donors for irregular abs yet. So minor cross matches are routinely done. I am in India and it is only the latest current guidelines issued out that have made mandatory, ab screen for donors & elimination of minor cross matches for us, now. It will be some time until all blood banks get into the routine.