Patient Antigen Typing

[JoyG]

Does anyone perform an antigen type on the patient if transfused within 3 months? i.e. if result is negative, can be reported but if result is positive, it is invalid?  or do you strictly follow the 3 month rule?  (not including molecular testing)

[Mabel Adams]

We don't record an official type within 3 months but if you apply logic you can learn useful things.  You can't always trust a negative--it depends on the antigen frequency, how much was transfused and when.  If someone got 10 units a week ago and now you are tying for e, your expectation would be different than if you were typing for Kpa.  Likewise, if they got 2 units 11 weeks ago, the impact would be lessened.  Then there are cell-separation techniques you can use to get valid antigen typing results.

 

We recently had a patient come in with a historic anti-E and a new anti-c which was reacting only with double-dose cells.  His nurse said he had been transfused recently in a big city hospital.  We called and found out that he had received 2 units less than a week prior and that they had detected anti-E and a "non-specific" antibody. Now he was anemic and needing blood.  His auto control was negative in gel.  We antigen typed him for c more for understanding what was going on with him than anything.  He typed perfectly c neg.  The odds that he happened to get 2 c neg units when the hospital was selecting only E neg are not very high.  For none of those c pos cells to be detectable in his sample less than a week after transfusion suggested to me that his "non-specific" antibody was probably an anti-c not reacting with all cells, they gave him at least 1 c pos unit and he was now anemic because he had destroyed that entire unit (or maybe both).  He was in liver failure to start with so his high bilirubin was hard to blame on the transfusion.  If it had been anti-K I wouldn't have thought it so likely that one of the transfused units would have been K pos so I probably would not have bothered with the typing at that time.

[David Saikin]

I only do it when deemed important. As I do most of my typings in gel it is fairly easy to detect mixed-field populations and so look at those typings in a different manner than a clean negative or positive result.

[Sandy L]

We proceed as Mabel.  We will not report the result on a transfused sample, but will evaluate # of units transfused and how recently.  It will sometimes help unraveling multiple antibody specificities.  We will just add a comment in the BB record that patient is "probable xyz neg or pos" and that the patient needs antigen typing on an untransfused specimen.  This morning we had a patient who received 2 RBC's in another hosptial exactly 2 months ago (antibody screen negative at that time).  Today patient has anti-c plus anti-E plus something else.  We were eventually able to eliminate other clinically significant antibodies and found that all of the extra reactions were cells marked as Bg positive by Ortho.  Patient is currently DAT negative.  As with Mabel's patient, c and E typings were totally negative.  Other antigen types were either cleanly negative or strongly positive with no mixed field reactivity.  I do not believe the patient has any surviving donor cells, however we will wait 3 months post any RBC transfusions before we officially antigen type.

Edited August 19, 2013 by Sandy L

[BBCLS]

Same as Sandy and Mabel.

[SMILLER]

No.