I have had a strange (couple) of cases today - one A- and one AB-, both with weak anti-A. Controls and other samples (around 300) run that day all had strongly reacting groups, the sample quality was satisfactory, the results done manually had the same results using two different batches of cards, so there is no doubt the results were genuine.

 

Patient A- was a new patient, preop and the sample has been sent to the BTS reference centre for confirmation, patient AB- was a patient who had been seen before and looking back at the analyser results it had been flagged as a 2+ reaction and been ignored by the technician.

 

I have never seen weak reactions in A-groups (though occasionally even in neonates so l was immediately alerted and have reported the samples both as 'possible A subgroup' and flagged them as transfuse only O Neg until confirmation.

 

Am I barking up the wrong tree? Could transfusion of A or AB respectively cause an immediate transfusion? Am I right to worry that a technician would 'ignore' this, or are they seeing something that I am missing?

 

The fact that a more experienced technician has 'ignored' this is making me doubt myself and think I am overreacting...

Well you should certainly not ignore this type of result.  It could be due to a weak sub-group of A (A3, Ax, etc) or something wierd going on with a normal A gene but a transferase that's not working properly.  You probably wouldn't cause a transfusion reaction if you transfused A but these are the interesting cases that make our life interesting.

As Anna says, these results should not be ignored under any circumstances, but I rather got the impression that the forward group was of normal strength and that it was in the reverse group where there was a weak reaction with the A cells. Am I correct, or barking up the wrong tree?

If I am correct, are you absolutely certain that you are dealing with an anti-A, and not an anti-A1 or an anti-M or antibody of a similar "cold" type? Have you typed the patients' red cells with Dolichos biflorus? Have you tested the plasma against about three A1 and three A2 red cells? Have you set up a room temperature panel? Have you performed the reverse group at 37oC?

Sorry, so many questions and, at this stage, absolutely no answers!!!!!!!

As Anna says, these results should not be ignored under any circumstances, but I rather got the impression that the forward group was of normal strength and that it was in the reverse group where there was a weak reaction with the A cells. Am I correct, or barking up the wrong tree?

 

Wrong tree - it's the anti-A, the forward group (not the cells) that are showing a 2+ reaction...

 

Not seen this in 13 years, and neither has my boss and I get two on one shift!

Well you should certainly not ignore this type of result.  It could be due to a weak sub-group of A (A3, Ax, etc) or something wierd going on with a normal A gene but a transferase that's not working properly.  You probably wouldn't cause a transfusion reaction if you transfused A but these are the interesting cases that make our life interesting.

 

This was my thought but I was concerned about the possibility of a transfusion reaction. I was more concerned that a colleague had reported it off without even so much as a comment and the patient was not marked as 'unsuitable for electronic issue'

Ah sorry. Not so much "barking up the wrong tree", as being "barking mad"!!!!!!!!!

I still agree with Anna dn with you (particularly anything concerning ABO). It should have been resolved, otherwise the BMS is performing an in vivo crossmatch and gambling.

Was it possible that either patient had recently been transfused with several units of O cells? I know you said one patient was new to you, but they may have gone elsewhere.

An update - the reference centre said that it didn't fit with any described A-subgroup and we are to treat as group B until they have investigated further

Just an update as someone clicked 'like'. Still no answers from the reference centre - I think someone there may get a paper out of this case