A man is O neg, and neg for antibody screen. He gets a transfusion from a compatible blood donor. 2 weeks later he is re-screened for antibodys and it is positive for Anti-D and Anti-C. How does this happen?

I am assuming that the transfused donor unit was O Negative? It is possible that the transfused donor unit was C Positive, and therefore G Positive. So the patient may now be producing Anti-G (or Anti-G plus Anti-C.) The reaction pattern that you will see when you perform an Antibody Identification Panel on a sample with Anti-G will look like a mixture of Anti-D plus Anti-C.

You can confirm anti-G specificity by adsorbing your serum onto "dC" red cells, eluting, and then testing the eluate against "Dc" cells (or the other way around). If the eluate reacts with the second cells, you have anti-G .

Another possibility is that his antibodies were below detectable levels and just the fact that he was exposed to some one elses RBCs can stimulate an increase in his antibodies even if the units are antigen negative. This is not common but I have seen it happen. A history of previous transfusions would help.

I have a 97 year old woman in house this week with the D, C phenomenon. I do not differentiate for G, I just give D neg units neg for C. It really is the practical way to do it. Of course we have known about her for a few months in our case.

As for your patient, Yes, could be both either of the previous suggestions. Although I have not personnally seen the Rh's drop in titer much. Case in point my in house patient whose titer has been 4+ for 7 months, despite transfusion of antigen negative units and no other stimulus.

I am leaning toward the Anti-G in your case. In the mean time, you need to give D negative units that are neg for C. Differentiation only becomes an issue when you are dealing with OB.

I am assuming that the transfused donor unit was O Negative? It is possible that the transfused donor unit was C Positive, and therefore G Positive. So the patient may now be producing Anti-G (or Anti-G plus Anti-C.) The reaction pattern that you will see when you perform an Antibody Identification Panel on a sample with Anti-G will look like a mixture of Anti-D plus Anti-C.

Hey Donna,

Would this same pattern occur in Ficin treated panel cells?:)

Hey Donna,

Would this same pattern occur in Ficin treated panel cells?:)

Yes. G is, of course, an Rh antigen.

I do agree that this is probably anti-G, but, in all but the strongest examples of anti-G, you will see that the antibody reacts stronger with C+D- (in most cases r'r) cells, than with C-D+ (in most cases R2R2) cells, and this sometimes gives a clue that that it is anti-G +/- anti-C, rather than anti-D+C.

:):)

I have a 97 year old woman in house this week with the D, C phenomenon. I do not differentiate for G, I just give D neg units neg for C. It really is the practical way to do it. Of course we have known about her for a few months in our case.

As for your patient, Yes, could be both either of the previous suggestions. Although I have not personnally seen the Rh's drop in titer much. Case in point my in house patient whose titer has been 4+ for 7 months, despite transfusion of antigen negative units and no other stimulus.

I am leaning toward the Anti-G in your case. In the mean time, you need to give D negative units that are neg for C. Differentiation only becomes an issue when you are dealing with OB.

I agree with what you are saying; however we just had a 53 year old male with a history of anti-c and anti-S (identified in October of 2009) who, as of two days ago, only has anti-S detectable in his specimen. I showed the case to our student and explained how unusual it is for the Rh antibodies to decrease in strength that way. She has been fortunate that we have had so many unusual patients in the short 2 weeks she has been here. We aren't really that big and most of our patients are "normal" or have "normal" antibodies.

I worked with a lady who had her anti-D drop below detectable levels. The problem seems to be that not everyone's antibodies have read the books on how they are supposed to act. Some just manage to do the unexpected. The question with her would be, will her anti-D come back if transfused with D negative RBCs? Maybe, maybe not. Only one way to find out and that's transfuse her.

Perhaps another possiblity is that one or both of the transfused units actually contained anti-D and anti-C, and that this is a passive antibody.