A blood sample from an antenatal clinic (9 weeks gestation) showed 3+ reactions in the antibody screen. Antibody identification show 2+ reactivity in IAT and 4+ reactivity in enzyme techniques, with a negative autocontrol. The patient's phenotype is C+c+E+e+K-. The sample was sent to a reference lab, which reported non-specific reactions in IAT and enzyme , with no antibodies detected by LISS . 

DAT: Negative 

Any explanation for this results why strong reaction in screening and antibody identification but no alloantbodies 
 
 
 
 

My immediate thought is that they should have sent the sample on to Red Cell Reference at the IBGRL.

If they have also detected an antibody by IAT and enzyme techniques, that is not reacting with autologous red cells, and, as the DAT is negative, the specificity needs to be sorted out as early as possible in the pregnancy, in case the antibody is 1) clinically significant and 2) becomes more potent during the pregnancy.

That's what my concern too. 

Another question how does anti f works? Does is react with LISS tube IAT?

Just wondering due to patients phenotype, could it be Anti-f?

It is most unlikely to be anti-f, as this specificity will not react with either R1R1 or R2R2 red cells (I presume that you are using both antibody screening cells and antibody identification panel cells that have these phenotypes represented).

Anti-f reacts with red cells where the c and e antigens are the result of an RHCE*ce haplotype where, for want of a better way of putting it, the c and e antigens are the result of the RHc and RHe genes being in the cis position - NOTE THAT THIS TERMINOLOGY IS (KNOWINGLY) WRONG!

Like all Rh antibodies, anti-f reacts most strongly with its cognate antigen on red cells that have been treated with a proteolytic enzyme (such as papain or ficin), but will very often react with untreated red cells by IAT.

Thanks Malcolm.  

 If auto  and DAT are negative I would always think of HFA. 

If it is reacting with al cells other than the patient's own red cells, then the chances are that it is an antibody directed against a high prevalence antigen, BUT, it could be a mixture of more than one (more common) specificity or, worse, a mixture of an antibody directed against a high prevalence antigen (e.g. an anti-Vel) and against a polymorphic antigen (e.g. an anti-Jk^a).

This is why I say it is important to actually have the specificity/specificities sorted out as soon as possible, because the foetus/newborn may need a transfusion, and/or the mother may need a transfusion (possibly both, and possibly in a hurry).  There may be very little time towards the end of the pregnancy.

The antibody may well have a specificity that is not clinically significant to either the foetus/newborn or the mother, but it is best to know.

Maybe we can try by using the mother's serum to react with the father's red cells (if they are not ABO type compatible, using R1R1,R2R2,rr red cells adsorb the allo-antibodies separately before doing elution ). I am not sure if I can make myself clear.

The elution react with the father's red cells. Using those three Rh types, I reference auto-antibodies adsorption, because I am not sure if there is a mix of anbodies in the mother's.