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woebegone1997

R1R1 patient with only anti-E: R1R1 RBC?

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Previously (before I joined this organization), my BB had the policy of issuing E _and_ c (big E, little c) negative RBCs if a patient had _either_ an anti-E or an anti-c and the patient was negative for the other antigen; i.e., patient has anti-E and is c neg., or has anti-c and is E neg. We discontinued this practice over 10 years ago, and as far as I know, this had no significant impact on the patients. At our medical director's initiative, we started this practice again for patients with anti-c. The medical director would like to do this also with anti-E patients. However, this would have significant financial impact. Anti-E is among the most commonly identified antibodies among our patients. Screening for E neg units is not difficult (~70% of population), but finding E and c neg brings the number down to about 14%. To make this number even lower, I know that my blood supplier pre-screens the units and reserves at least a half to 2/3 of R1R1s as stock, so the chances of finding one from our general inventory would be somewhere around 5-7%. To order an R1R1 product from our blood supplier would add about $180 per unit.

So, a couple of questions:

1. Is anyone else giving R1R1 RBCs to R1R1 patients with just one of the antibodies?

2. Is anyone aware of any literature that studied the likelihood of an R1R1 patient with an anti-E to develop an anti-c?

I hope I clearly presented the situation. :wacko: If you have questions about the situation or what I'm asking, please let me know. Thanks for your input!

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I can only answer the first question. At my previous facility we would order c=, E= units for patients with anti-c, but if the patient only had anti-E we would not order c= on a routine basis. It was not our practice to test the patient for the c antigen if the antibody suspected was anti-E (edit: except during the situations below), so we would not usually know the patient's c typing anyway.

Exceptions to this general rule would be patients with a history of sickle cell anemia (we gave Rh/K matched at least) and patients with warm autos who were being frequently transfused. If I had to guess, my supervisor would also make an exception for other frequently transfused patients who were c= (i.e. aplastic anemia or similar) who had anti-E.

Edited by Teristella
Clarification

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I have the advantage in that I work in a Reference Laboratory in London with an enormous stock of units.

That having been said, we would give c Negative E Negative blood to all R1R1 patients with a haemoglobinopathy, or an auto-antibody (or any other condition that means they are likely to become transfusion dependent) and to females of child-bearing potential, even if they have not made an anti-c or an anti-E, as a sort of prophylaxis to stop them making these specificities (although of course, "naturally occurring" anti-E-like mimicking specificities still occur).

Any patient that falls outside this, we just give the cognate antigen negative.  Remember, the vast majority of patients who receive a transfusion either die within 12 months,or never require further transfusions throughout their lives, and so it really isn't worth giving R1R1 blood to these others.

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There is an article on this topic published in Immunohematology 2005; 21:94-96 by John Judd et al "On a much higher incidence of anti-c in R1R1 patients with anti-E".

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We give all patients with Anti-E, blood that is c antigen negative. Until a few months ago, we had several patients who were chronically transfused that required both E, c negative units so we stocked two at all times. The 18th Edition of the AABB Technical Manual, p. 331 states: "When seemingly compatible E negative blood is transfused, (to a patient with anti-E who most certainly has been exposed to the c antigen as well), it is most likely to be c positive and may elicit an immediate or delayed transfusion reaction. Therefore, some experts advocate for avoiding the transfusion of c-positive blood in this situation."

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It is the policy at our facility to give E=c= RBCs when patient has anti-E and types also as c= or if c pheno is unknown or cannot be done due to very recent transfusion, but we do not type the units for E when patient has anti-c only. In this case, we only give c= units.

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On 8/12/2016 at 9:38 AM, WisKnow said:

It is the policy at our facility to give E=c= RBCs when patient has anti-E and types also as c= or if c pheno is unknown or cannot be done due to very recent transfusion, but we do not type the units for E when patient has anti-c only. In this case, we only give c= units.

This is our policy also.  Almost all c negative units will be E negative so we trust to statistical luck for patients with anti-c.  We started this policy long ago when one edition of the Technical Manual recommended it.  When the wording was changed to say some recommend it, I considered our situation and continued the policy.  We are several hours away from our blood supplier so if we have caused an anti-c to develop we can't get c negative blood imported quickly like we could if we were just across the city from the supplier.  We could screen for it but would have similar results as described above after the supplier saves out the R1R1 units.  Also, our region has a lot of small hospitals that don't do Ab IDs.  I feel that this policy preserves the chance of finding crossmatch compatible blood or even to expect that O negative will be compatible with a patient with anti-E in an emergency (Rh negative is about 99% E negative).  I have never had a hemorrhaging patient with anti-E saved by this policy so maybe it is overkill, but that is our logic.  We have the added benefit now that our supplier sends us a batch of 10 historically negative units (for various random antigens) every Friday that usually includes some c negative units.  That has been a big help.

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On 8/12/2016 at 11:38 AM, WisKnow said:

It is the policy at our facility to give E=c= RBCs when patient has anti-E and types also as c= or if c pheno is unknown or cannot be done due to very recent transfusion, but we do not type the units for E when patient has anti-c only. In this case, we only give c= units.

This is our policy.

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On 11/08/2016 at 6:22 PM, woebegone1997 said:

 Anti-E is among the most commonly identified antibodies among our patients. Screening for E neg units is not difficult (~70% of population), but finding E and c neg brings the number down to about 14%. 

If you have 70% of population E neg and 14% E neg c neg, that's mean most of your patients are R1r. I would prefer to perform Rh phenotype on patient, if patient is c pos, There is no need to provide E neg c neg blood.  If patient has anti-c than you have to provide c neg E neg blood, it's very difficult to find unit which is c neg E pos. 

 

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The most recent FDA report of transfusion fatalities included one who had 3 antibodies but got emergency release blood.  The emergency units were negative for the E & K but c positive and the patient made the fatality list so that's not a good outcome.  Rare, but I'm feeling more justified in our current policy.

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