typing RBCs for low incidence antigens

[Mariom01]

Hi ,

we currently perform Cw, Kpa, Lua and Wra antigen typing on all RBC units provided as 'least incompatible ' by IAT crossmatch to multi transfused patients with highly complex antibody profiles and /or auto immune haemolytic anaemias with warm free IAT antibodies.

Does any other establishment perform this?

I would be interested to know of others thoughts. Is it justified on the basis of the very low number of HTRs attributed to the transfusion of low incidence antigen positive units or does it contribute significantly to the safety of the patient ?

[David Saikin]

How many of these abs are missed in routine ab screenings? There must be some but we never hear of reactions to these.

[Malcolm Needs ☆]

We would just not consider typing for Cw, Kp(a), Lu(a) or Wr(a), except in exceptional cases, where the patient has so many other antibodies that we just check them for Cw, for example< if we know that the patient also has an anti-Cw. That, however, is NOT because we consider these antibodies to be clinically significant (with the notable exception of anti-Wra), but because, if the unit is negative for 5 other antigens, then we want to know if it is likely to be compatible by IAT. If the anti-Cw is only active by enzyme technique, but not by IAT, and the unit is Cw+, we would still give it as cross-match compatible.

I've cited this article before, so for those that remember, sorry to repeat myself, but you may find it worthwhile reading Garratty G. How concerned should we be about missing antibodies to low incidence antigens? Transfusion 2003; 43: 844-847 (Editorial). Admittedly, George is writing about electronic issue of blood, and screening cells that do not express these antigens, but, that notwithstanding, the answer is a resounding "NO"!!!!!!!!!!!

:salute::salute:

[Mariom01]

We would just not consider typing for Cw, Kp(a), Lu(a) or Wr(a), except in exceptional cases, where the patient has so many other antibodies that we just check them for Cw, for example< if we know that the patient also has an anti-Cw. That, however, is NOT because we consider these antibodies to be clinically significant (with the notable exception of anti-Wra), but because, if the unit is negative for 5 other antigens, then we want to know if it is likely to be compatible by IAT. If the anti-Cw is only active by enzyme technique, but not by IAT, and the unit is Cw+, we would still give it as cross-match compatible.

I've cited this article before, so for those that remember, sorry to repeat myself, but you may find it worthwhile reading Garratty G. How concerned should we be about missing antibodies to low incidence antigens? Transfusion 2003; 43: 844-847 (Editorial). Admittedly, George is writing about electronic issue of blood, and screening cells that do not express these antigens, but, that notwithstanding, the answer is a resounding "NO"!!!!!!!!!!!

:salute::salute:

Thanks - this very much confirms how I want to proceed . I had reviewed the article cited and used the relevant points to support my suggestion that we no longer perform these tests . It's useful to know what other centres do .