what is the importance of ruling out little "c" antigen?

[trisram]

I ruled in Anti-E in my patient's antibody ID panel. Then my supervisor told me to antigen type for little "c" for both patient and all donor cells.

She explained it to me, but I didn't quite fully understand what she meant.

Anyways, can anyone explain to me?

Thank you in advance for your time and help.

Edited October 30, 2009 by trisram

[Malcolm Needs ☆]

Do I take it that the patient was a female of child-bearing potential (hateful phrase)?

If so, I can quite see your supervisor's concern.

In terms of "common" antigens, the c antigen is the second most immunogenic, behind the D antigen.

If a person who is c- is transfused with c+ blood, there is a very high likelihood that they will produce an anti-c.

Anti-c is amongst the three most common causes of clinically significant haemolytic disease of the newborn/foetus.

Therefore, if the patient is c-, you would not want them to be stimulated to produce anti-c, and you would give c- blood.

This only pertains if, for example, the patient is an R1R1, rather than, say, an R1r, and is female.

I attach an essay I did a few years ago concerning this and other occasions when you might give phenotyped blood.

It may be of use, or it may not, but it is there if you want to read it.

Phenotyped Red Cell Transfusions.doc

References.doc

[trisram]

Thanks so much Sir. But my patient was male though.

Here is what happened?

1) I got a request for 2 units of blood

2) I did an Ab screen on the patient

3) the screen came up positive

4) so I did an ID panel

5) I was able to rule in Anti-E and Anti-K

6) Then I antigen typed 2 ABO compatible units. They are both negative E and negative K

7) I also did an initial spin cross match and a gel cross match for for both donors and with patient plasma. Results were negative, so units are fully compatible.

I though I was finished, then my supervisor told me to also antigen type for c. Why I am wondering is why is this situation so special to require c antigen typing?

I understand what you are saying about the patient being antigen c positive, and it would not be wise to give him/her c negative blood. Then why don't I antigen type for c everytime for everyone? But wouldn't the gel crossmatch be able to rule out any Ab/Ag non-compatibilty between donor and patient?

Basically, I was just wondering, why is this situation different that I had to do an c antigen typing?

Sorry, I am training in blood bank, iand t has only been a few weeks. Usually, I work microbiology and core lab, but we are short of staff, so they have me filling in for the time being.

Thank you for your answer, it has been very enlightening.

T. Ramon, MT(ASCP)

Do I take it that the patient was a female of child-bearing potential (hateful phrase)?

If so, I can quite see your supervisor's concern.

In terms of "common" antigens, the c antigen is the second most immunogenic, behind the D antigen.

If a person who is c- is transfused with c+ blood, there is a very high likelihood that they will produce an anti-c.

Anti-c is amongst the three most common causes of clinically significant haemolytic disease of the newborn/foetus.

Therefore, if the patient is c-, you would not want them to be stimulated to produce anti-c, and you would give c- blood.

This only pertains if, for example, the patient is an R1R1, rather than, say, an R1r, and is female.

I attach an essay I did a few years ago concerning this and other occasions when you might give phenotyped blood.

It may be of use, or it may not, but it is there if you want to read it.

[Malcolm Needs ☆]

The case being that the patient was male, I honestly do not know why the supervisor was so worried, unless the patient was, or was likely to become transfusion dependent (in which case, I would also be wary of them making an anti-c; they had already shown themselves to be a responder by making anti-E+K).

[trisram]

I think perhaps she was just trying to show off how knowledgable she is in blood banking, and that the c antigen typing was unnecessary. If that is truly the case, all she accomplished was confuse me more.

[Malcolm Needs ☆]

I must say, except in the circumstances I alluded to in my earlier posts, it does sound somewhat over the top to me too!!!

[trisram]

I think it was more of a computer program thing than an actual testing thing. In our computer program, there are two different codes for Anti E, one is ABGE and the other is ABIGE. If ABIGE is used, then the patient cells should be c postive.

I think it is because I used the ABIGE, that I needed to do the antigen c testing, just to make sure if the units and patients were really c posiitve. I couldn't change to ABGE, because I saved it already. I think that is what my supervisor was trying to say.

[David Saikin]

There is also the "thought" that in many instances when anti-E is demonstrated an underlying anti-c may be present but undetected. I have not found this to be true during the course of my blood banking experience. If I am able to r/o the anti-c, I feel good about not screening units for this ag and chances are I wouldn't screen anyway (even if a woman of child-bearing age). Decades ago, we used to screen our prenatals for c, but haven't done that in a long time.

[Malcolm Needs ☆]

There is also the "thought" that in many instances when anti-E is demonstrated an underlying anti-c may be present but undetected. I have not found this to be true during the course of my blood banking experience. If I am able to r/o the anti-c, I feel good about not screening units for this ag and chances are I wouldn't screen anyway (even if a woman of child-bearing age). Decades ago, we used to screen our prenatals for c, but haven't done that in a long time.

Hi David,

I'm not saying you are wrong about the women of child-bearing age (I wouldn't dare!), but in my attachment I do make an arguement as to why I think this should be done.

IT DOES NOT MEAN THAT YOU HAVE TO ACCEPT MY ARGUEMENT, I HASTEN TO ADD!

[AMcCord]

See AABB Technical Manual, 16th ed, page 404 'Concomitant Rh Antibodies'. This may be what your supervisor was talking about. The same material is on p 327-328 in the 15th ed.

[Eagle Eye]

I have seen several example of anti-E with 2 or 3 c+ reacting on Gel panel A....All common allos ruled out...and hen we used enzyme treated panel we confirmed the presence of anti-c.

[Malcolm Needs ☆]

I have seen several example of anti-E with 2 or 3 c+ reacting on Gel panel A....All common allos ruled out...and hen we used enzyme treated panel we confirmed the presence of anti-c.

We use an enzyme panel automatically, together with an IAT panel.

Does this mean that you do not necessarily do the same?

:confused::confused:

[Eagle Eye]

No We do not run enzyme panel automatically. If we have clear cut antibody(ies) from panel A, we do not run enzyme panel. We run enzyme panel when we have multiple allos and panel is not conclusive and AC is negative. Most warm autos gets enhanced by enzyme and doesn't give us much inforrmation when we run enzyme panel. Other reason we might run panel C would .be when we suspect mixture of enzyme sensitive and resistent antibodies.

We are not IRL. I believe most IRL runs IAT and enzyme same time(most of them by tube)/

DO you use Gel and run enzyme all the time? If yes, don't you get so many inconclusive panels?

[Antrita]

My old pathologist use to ask me about Anti-c when I had an Anti-E antibody. I finally realized that he was just getting them backwards. It can be hard to R/O Anti-E when a patient has an Anti-c. Maybe this is the problem.

Antrita

[trisram]

See AABB Technical Manual, 16th ed, page 404 'Concomitant Rh Antibodies'. This may be what your supervisor was talking about. The same material is on p 327-328 in the 15th ed.

Thanks , but I don't have a manual. What does it say ?

[Malcolm Needs ☆]

No We do not run enzyme panel automatically. If we have clear cut antibody(ies) from panel A, we do not run enzyme panel. We run enzyme panel when we have multiple allos and panel is not conclusive and AC is negative. Most warm autos gets enhanced by enzyme and doesn't give us much inforrmation when we run enzyme panel. Other reason we might run panel C would .be when we suspect mixture of enzyme sensitive and resistent antibodies.

We are not IRL. I believe most IRL runs IAT and enzyme same time(most of them by tube)/

DO you use Gel and run enzyme all the time? If yes, don't you get so many inconclusive panels?

Well, it is true that I am from a Reference Laboratory, but that having been said, the BCSH Guidelines in the UK strongly advise that an enzyme panel is run as well as an IAT panel, and so most Hospital Blood Banks will also run an enzyme panel.

I do agree with you that, in the case of a warm auto (and many times in the case of a "cold" auto) the enzyme panel adds nothing.

Yes, we run our enzyme panel in gels, but, unless there is an auto present, this panel is often extremely useful.

:)

[Malcolm Needs ☆]

My old pathologist use to ask me about Anti-c when I had an Anti-E antibody. I finally realized that he was just getting them backwards. It can be hard to R/O Anti-E when a patient has an Anti-c. Maybe this is the problem.

Antrita

As a Reference Laboratory, we have access to plentiful supplies of R1Rz, and so would always rule out/in an anti-E accompanying an anti-c, but in 99.99% of cases (or more), clinically, it makes absoultely no difference whatsoever! If you are going to transfuse a patient who has anti-c, you would normally go for R1R1 anyway (I am accepting the fact that I am ignoring rare Rh patient types for now) and, in the case of a pregnant lady, the level of anti-c is usually far more important than the level of anti-E (and, if the level of anti-E is that high, and considered more important than the level of anti-c, the reactions will be noticably stronger with c+E+ red cells than with c+E- red cells).

I do, therefore, see where you are coming from and agree.

:)

[MCrosby]

My Reference Lab’s practice is to honor c if the patient demonstrates an anti-E (and they are Rh positive) and they are antigen negative for c, regardless of sex or age. Since c is so antigenic, it’s just good practice. Do you really want to run the risk of them forming an anti-c? And if their immune system is ramping up to form anti-c, would it run be reasonable to believe that it may start forming antibodies to other blood group antigens as well? An interesting article in Immunohematology (Vol 21,No3,2005) finds that anti-c in R1R1 patients with anti-E is higher than one would think. I believe anti-c showed up in Gel or enzyme treated panels, where it wasn’t showing in tube (I’ll have to find the article), but in any case no one wants to work up a transfusion reaction if it could have been prevented.

[Malcolm Needs ☆]

Yes, I would agree with you, but I would take into account sex, age and clinical condition.

[bbbirder]

I tell our techs (all generalists) that it is a good idea to do the antigen typing for all the Rh antigens whenever a patient has made any antibody in the Rh system (except anti-D). I believe that it is a good idea to get antigen typing before transfusion for future reference.

I also personnally think that providing c-neg blood in a c-neg patient who has already made anti-E is a good idea.

The problem we encounter is a computer system that doesn't allow reminder messages attached to any antibodies. It is very difficult for generalists to remember all the complexities in BB.

What the reference labs do routinely, can be different from what hospital based transfusion services do routinely.

Linda Frederick

[Malcolm Needs ☆]

I tell our techs (all generalists) that it is a good idea to do the antigen typing for all the Rh antigens whenever a patient has made any antibody in the Rh system (except anti-D). I believe that it is a good idea to get antigen typing before transfusion for future reference.

I also personnally think that providing c-neg blood in a c-neg patient who has already made anti-E is a good idea.

The problem we encounter is a computer system that doesn't allow reminder messages attached to any antibodies. It is very difficult for generalists to remember all the complexities in BB.

What the reference labs do routinely, can be different from what hospital based transfusion services do routinely.

Linda Frederick

Yes Linda, I see where you are coming from, but a colleague of mine has just had a horrible case where a D- lady with bleeding varicies made anti-D. She had an anti-D, but they did not do her other Rh antigens. She then went on to make an anti-c because she turned out to be an r'r', so it may also be worthwhile doing the other antigens in the case of someone who has made anti-D!

In the case of a 70-year-old male undergoing a one-off surgical procedure, such as a THR with an anti-E, who was R1R1, I wouldn't worry if he made an anti-c too!

:eek:

[eric1980]

I've read from somewhere that patient who develop anti-E are more likely to develop anti-c as well. So we usually type donor RBC for absence of c antigen. However my lab didn't type the patient for expression of c antigen, though. =/ Now I wonder...

[nmpoupard]

In the presence of anti-E we would antigen type the patient for the c antigen. If we were unable to type the patient for c due to recent transfusions or pregnancy, we would test with an enzyme panel to rule out the presence of anti-c. Not very often, but often enough to be concerning, we would detect an anti-c in enzyme only in addition to the anti-E. This became our standard of practice.

[Trek Tech]

It is easier to keep a c= patient from making anti-c than it is to do rule outs when a patient has anti-c and anti-E. Look at a panel of cells and I think you would agree. Most of the hospitals in my area (as well as our reference lab) have a policy to give c neg units if the patient has Anti-E and is c neg.

[nmpoupard]

How do you deal with the cost of antigen typing donor units for the c antigen as a preventive measure?