Antigen typing on DAT positive

[gagpinks]

Hi 

How does or what method reference lab use to perform phenotypes ( Fya ,Fyb ,Jka Jkb S s etc). If patient's DAT is positives.?

If patient with positive DAT e.g.. ( lymphoma or CLLor any drug induced ) and develop anti body how would you do antigen typing on theses patient?

 

[Malcolm Needs ☆]

Firstly, and if possible, we would use an IgM monoclonal agglutinating antibody.

Secondly, we can elute off the auto-antibody using mild treatment with DTT or ZZAP, leaving the red cells relatively intact (relatively, because some antigens are denatured by this, while some others are considerably weakened).

Thirdly, and more commonly now in the UK, we can perform genotyping (but it has to be remembered that genotyping is only a prediction of what antigens may actually be expressed on the red cell surface).

[gagpinks]

Thanks Malcolm 

I was doing one of the IPEX excercise and there was case where baby had DAT positive due to maternal antibody. Therefore result on phenotypes( Fya  Fyb)  are not reliable.  In this case you can use chloroquine phosphate to de nature Off antibodies.  So I thought they might be using for all above cases. I knew about DTT and ZZAP. But never came across about CDP. 

[gagpinks]

1 minute ago, gagpinks said:

Off antibodies. 

Sorry IgG antibodies. 

[Malcolm Needs ☆]

Yes, I'm sorry, I meant to mention chloroquine phosphate to elute antibodies, but, once again, you have to be careful, as this will also denature some antigens and weaken others.