Antigen typing units for cross-match

[swadeadesoye]

What policy do any Blood Bank have on antigen typing units for any patient with an antibody to low-frequency antigen.

example: Anti-Jsa or Anti-Cw.

Please share your views or policies at your Hospital Blood Bank.

At my previous hospital, we were not required to antigen type units for Cw because compatible donor units for transfusion are easy to find.

My current Hospital Blood Bank do ask for Cw negative units from a Reference Blood Center instead of cross-matching compatible units at the AHG phase for transfusion.

Kindly share your views, thoughts and policy at your Hospital Blood Bank on low-incidence antigens.

Adenle

Member

[donellda]

We usually get our low incidence antigen typed units from ARC. They have a better supply of antisera and cells than we do. For patients with Anti-Cw, we have been giving AHG compatible C negative units. The Cw antigen is usually present when the C antigen is present so if you give C negative units you are pretty safe that Cw is not there.

[swadeadesoye]

Thanks Donellda for your quick response.

On the subject of Anti-Cw, is it possible to identify an Anti-E, Anti-Cw and Anti-c (little c) together with Anti-Bg?

It doesn't look plausible to me but that is the results we got from a Reference Lab.

Is it possible for an R1wR1 individual produce Anti-c(little c), Anti-Cw in

combination with Anti-E and Anti-Bg.

Kindly share your professional opinion.

I will like to hear from anybody who has come across such results.

Thanks.

Adenle

Member.

[bbkdiane]

There are many low frequency antibodies for which no commercial typing sera exist. In these cases, we IgG Coombs match the intended unit. Since our Misys system has antigen-antibody logic built into the QA table, the system will alert when no antigen typing has been performed on the donor unit; we enter a reason code such as UNAG (unable to antigen type unit). The question I always hear is: what if the low frequency antibody is so weak that it is not demonstrable? The odds of a low titer, low frequency antibody matching up with the antigen positive unit ...well, the odds are probably in the magnitude of winning the lottery.

Should we worry? Probably not. Real worries: patient identification errors by nursing staff/phlebotomy when drawing BBK samples.

[Dawn]

For a patient with anti-Cw, we will perform a full XM but do not require the units to be tested for the antigen.

Anti-Cw and most of the other low-frequency antiseras are no longer available as FDA-licensed reagents.

If a patient has multiple antibodies and anti-Cw is one of them, it is worth the trouble to type the units for Cw. However, if anti-Cw is alone it seems a waste of a precious resource to test units.

[N Mullis]

"Is it possible for an R1wR1 individual produce Anti-c(little c), Anti-Cw in combination with Anti-E and Anti-Bg."

In response to this question, are you certain that the patient has the R1wR1 phenotype? This infers, to me, that the patient was typed positive for the Cw antigen. In that case, it would be pretty unlikely that the person produced anti-Cw. Anti-c and -E are pretty common antibodies in R1R1 or R1wR1 individuals. "Anti-Bg" is a little vague - since "Bg" is not a specific antigen. Perhaps they just meant to convey the presence of antibodies to HLA antigens....