ABO Discrepancies

[ckcheng]

Please see the ABO discrepancies (reaction score 0 - 4+) below:

Gel reaction: Forward: Anti-A: 0  Anti-B: 0  Reverse: A1-cells: 0  B-cells 3+

Tube method: Forward: Anti-A: 0   Anti-B: 0    Reverse: A1-cells: w  B-cells: 3+s

Increased serum to cell ratio and incubated at RT: A1-cells got 1+

Since there is a big grade different between A1 and B cells, should we suspect it as an A subgroup? or use 4C or enzyme to enhance the A1-cell reaction?

Thank you very much.

 

 

[David Saikin]

You may not get much info from A subtyping, esp if the pt is actually a group O.  I think the only way to be sure of a group A status would be to try and absorb/elute anti-A from the pts rbcs.

[soozmlt]

How old is the patient? Is the patient immune compromised? We see this sort of back type

frequently in our oncology/elderly patients.

[galvania]

Also, what is wrong with the patient?  If they have certain types of leukaemia the A antigen can 'disappear'.  Has the patient had a marrow transplant?  Or a type of bowel cancer that can 'swamp' the A antigen with soluble A substance.

Or you could have a weak A subgroup (Ax or weaker) with a weak anti-A1

There are other possibilities but the 'normal' ones need to be checked out first

[ckcheng]

The patient is a middle-aged gentlemen. Neither a transplant nor an oncology patient. Sent to hospital because of pneumonia. Strange was the big grade different in the reverse group. Under what situation should I suspect it is an Ael subgroup?  Thanks.

[Yanxia]

I think at first step, test this patient's cells use anti-AB, if the reaction is stronger than with anti-A, then it is Ax type.

2nd, if the anti-AB reaction strength is the same with anti-A, then do adsorption and elution test, to see if there are A antigens on the cells.

3nd, test the cells use anti-H, to see if there is some kind of parabombay or more rarely bombay type.

As to the reverse group, I think we should add a tube of O cells as negtive control, to make sure the reaction when we add more serum or prolong the incubation time or incubation them at 4 degree C is actually anti-A.

This is my personally opinions

[Yanxia]

If the A antigen reaction only be seen in adsorption and elution test, I think it is Ael.

[Yanxia]

But with the use of monoclonal antibodies, I am not sure whether the reaction is so typical as book says. And some different A subgroup defined by serological method may have same genetic background, so I think the most important things is how to transfuse not the naming.

[ckcheng]

Patient's red cells has no reaction against Anti-A,B (actually most anti-A reacts with Ax cell nowadays). Group O cells was included in reverse group (increased serum to cell ratio,  and 4C incubation to avoid any cold auto-antibody interfere) during interpretation. Yes, you are right that monoclonal anti-A is not suitable in the absorption and elution study cuz IgM don't react with AHG.

Thank you very much for your help.

CK

[Yanxia]

you are welcome

[David Saikin]

On Saturday, April 09, 2016 at 10:59 AM, ckcheng said:

Patient's red cells has no reaction against Anti-A,B (actually most anti-A reacts with Ax cell nowadays). Group O cells was included in reverse group (increased serum to cell ratio,  and 4C incubation to avoid any cold auto-antibody interfere) during interpretation. Yes, you are right that monoclonal anti-A is not suitable in the absorption and elution study cuz IgM don't react with AHG.

Thank you very much for your help.

CK

I think you can still absorb and elute anti-A, whether monoclonal or not.  You are going to test for anti-A not an antiglobulin reaction.  We did this many times where I used to work

[Auntie-D]

Isn't everyone overthinking this? Weak reverse groups are not uncommon and it's a lot of effort to go to for a naturally occuring and totally normal phenomenon. Is the patient aged, immunosuppressed or on chemo?