antigen typing during pregnancy

[mollyredone]

I know you are not supposed to antigen type anyone who had been transfused in the last three months, but what someone who is pregnant?  Seems like those two go together a lot, but if it is a simple immediate spin or RT incubation, would it be accurate if she is showing a new antibody right before delivery?  She already had an anti-E and today, for her C-section, and is showing an anti-c.  I was going to antigen type her but couldn't find any info about whether it would be valid or not.

Thanks!

[Yanxia]

there is a method which  using a microtube( sorry, i am not sure how to call it), fill the tube with blood, then centrifuge it, the new generated red cellls are lighter so they are on the upper layer, they are the patients' own cells, the transfused cells are heavier, so they are on the bottom

[Yanxia]

and from my daily work, i find we can tell from the proportion of cells, if transfused is less, then on  the mix field result, the large part is the patient's own cells

[Malcolm Needs ☆]

Unless there has been a foeto-maternal haemorrhage so large that the baby has been exsanguinated, it should be fairly easy to type the mother.  If there is a mixed-field, the majority of the red cells should be maternal.

The only exception would be if the maternal antigen in question has a weak expression.

More of a worry would be if you need to perform adsorptions, where auto-adsorption should not be performed, as the foetal red cells could remove an alloantibody from the maternal plasma, particularly if multiple adsorptions are required.

[exlimey]

I agree with Malcolm - a typical FMH involves a very small volume of cells. Their presence should not interfere with antigen typing of the mother, especially if using reagents that are IgM.

Just curious.....what would you do if the mother typed c+? Would you "ignore" the anti-c? I know we've all been programmed to antigen type when we identify an antibody, but sometimes it seems pointless.

[mollyredone]

1 hour ago, exlimey said:

Just curious.....what would you do if the mother typed c+? Would you "ignore" the anti-c? I know we've all been programmed to antigen type when we identify an antibody, but sometimes it seems pointless.

No, I wouldn't ignore it.  But it is a part of our workup to antigen type the patient if they have not been transfused in 3 months for future reference and if I expect my techs to follow it, I wanted to make sure my workup was valid.

[exlimey]

1 hour ago, mollyredone said:

No, I wouldn't ignore it.  But it is a part of our workup to antigen type the patient if they have not been transfused in 3 months for future reference and if I expect my techs to follow it, I wanted to make sure my workup was valid.

I understand. Do you phenotype all eligible patients (un-transfused or not recently transfused), or just those that you expect to see again ?

[mollyredone]

1 hour ago, exlimey said:

 

3 hours ago, mollyredone said:

No, I wouldn't ignore it.  But it is a part of our workup to antigen type the patient if they have not been transfused in 3 months for future reference and if I expect my techs to follow it, I wanted to make sure my workup was valid.

I understand. Do you phenotype all eligible patients (un-transfused or not recently transfused), or just those that you expect to see again ?

 

No, we don't phenotype patients as a rule.  Just for DARA patients.  Other patients we just antigen type for suspected antibodies.