Hello again,

What is the frequency of the C, E antigens on D negative red blood cells? We have a male patient who received O Positive uncrossmatched emergency units in 2011. Now he is showing an Anti-D antibody. The tech who performed the crossmatches yesterday did only an immediate spin with an O Negative donor unit without ruling out Anti-C or Anti-E because the panocell results looked like Anti-D. The units were issued early this morning before a QA could be performed. I phenotyped the patient's initial T&S cells obtained before he received packed cells. Patient is type O Rh D=, C=, E= . What would be the probability of this patient forming either Anti-C and/or Anti-E as well? My ARC reference lab pathologist is on vacation, but I sent her an email asking this. Unfortunately, the patient is inhouse and symptomatic. Any help would be appreciated since I am new to BB mommahood.

I would check your SOPs as to what to do next, but looks like you need to run a few more panel cells to rule in/out anti-C and anti-E. You can't just say the patient probably won't make the antibody, you have to prove that it is not there. Many places will allow rule outs with 3 D-C+c+ and 3 D-E+e+ cells.

I agree with JMM that the first step is to finish the rule out antibody ID panel. Two D-C+c+ / D-E+e+ rule outs are sufficient for my institution.

If you are unable to rule out C or E, pull the segments from the transfused units and phenotype them.

I'd also go back and complete the Coomb's crossmatch.

Make sure you have segment leftover in the event of a transfusion reaction and the need for subsequent testing.

 

Does your procedure require the completion of a rule out panel prior to releasing blood products for antibody patients?

Does your institution require a Coomb's crossmatch for anti-D patients?

I would assume it's a yes for both in which case you should definitely report this through your occurrence management system. If you're in the US this requires a biological product deviation report to be submitted to the FDA.

As an aside, it seems as though your tech released blood without "complete serological testing".  As suggested, you will have to review your own policies regarding positive AB screens, but here we have to rule-out all significant Abs before considering a crossmatch. 

 

Besides that, regardless of the panel rule-outs and patient Ag typing, if the patient is producing atypical Abs (even if only -D), I am pretty sure that you need to perform an IS AND coombs crossmatch before saying a unit is compatible.

 

Scott

Hello again,

What is the frequency of the C, E antigens on D negative red blood cells? We have a male patient who received O Positive uncrossmatched emergency units in 2011. Now he is showing an Anti-D antibody. The tech who performed the crossmatches yesterday did only an immediate spin with an O Negative donor unit without ruling out Anti-C or Anti-E because the panocell results looked like Anti-D. The units were issued early this morning before a QA could be performed. I phenotyped the patient's initial T&S cells obtained before he received packed cells. Patient is type O Rh D=, C=, E= . What would be the probability of this patient forming either Anti-C and/or Anti-E as well? My ARC reference lab pathologist is on vacation, but I sent her an email asking this. Unfortunately, the patient is inhouse and symptomatic. Any help would be appreciated since I am new to BB mommahood.

The frequency is low, I believe less than 1%.  Some labs, like mine only require 1 heterozygous C+ and E+ cell to r/o C,E in the presence of Anti-D.  If that is your procedure, and your panel cells r'r and r"r were both negative (usually cell #5 and #6 ORTHO), then you should be fine. 

 

That said, the crossmatches should be repeated through AHG.  Maybe time for some competency refreshers?

Edited July 17, 201312 yr by jayinsat

You can dowload the antigen frequency chart from the Ortho website.

 

All of our patient's with history of antibodies get an AHG crossmatch.

This may be reportable to the FDA as well since AHG crossmatches were not performed. 

Simple antigen frequencies always seem to include both D+ and D- people so it is sometimes hard to get the frequency of D- units that are pos for C or E. C+ is more common than E+ and I agree that each is < 1% or so.  We allow the ruling out of E and C specificities in the presence of anti-D with a single heterozygous cell partly because it is so unlikely that a D neg unit will be positive--about in the range of the frequency of the Kpa antigen as I recall.

Have you tried an elution since the transfusion?  That would confirm some of the suspects.

I would check your SOPs as to what to do next, but looks like you need to run a few more panel cells to rule in/out anti-C and anti-E. You can't just say the patient probably won't make the antibody, you have to prove that it is not there. Many places will allow rule outs with 3 D-C+c+ and 3 D-E+e+ cells.

 

Ruling out with only heterozygous cells (with few exceptions, e.g. Anti-K) is risky business.  I don't allow my staff to do that and I don't recommend it.

• There are plenty of examples of antibodies that react with homozygous cells only (due to sensitivity of the test and concentration of the antibody) ... so you will get a negative result with heterozygous cells whether you run 1, 3 or 999 of them.
• Sure, if you miss such an antibody, it is weak and will likely not cause a noticeable 'reaction' ... you'll likely see it better next time around.  Oooor maybe you won't, some patients never pass that threshold and continue to react with only homozygous cells ... so you'll just keep wondering why the patient keeps coming back for more transfusions and perhaps rising chemistries, positive DAT, etc.

The 3+3 rule is often misinterpreted/simplfied.  In reality, we 'rule out' with 1 cell every time an antibody screen is deemed negative (e.g.. no antibody identification is performed, 2 more negative cells for each antigen is not sought, etc.).  This is ok as long as you are testing using homozygous cells for 'all', i.e. most 3-cell screening kits. 

 

As far as finding 'D-neg, C-pos and/or E-pos' reagent cells to determine if the Anti-D is masking Anti-C and/or Anti-E ... good luck!  Those are rare cells not seen often enough on panels.

 

Bottom line:  If patient is producing Anti-D (i.e. not passively acquired from a 'pure and only Anti-D' injection), we rule out Anti-C and/or Anti-E only if

a) we can locate the cells to do so ('never' happens)

or

the patient is positive for C and/or E respectively. 

If we cannot, the report is "Anti-D, Cannot rule out Anti-C and Anti-E" (whichever applies, most often they both apply). 

 

To address the original question:

Yes, we type Rh-neg (D-neg) RBCs for C and/or E as applicable.

Yes, we do perform an extended crossmatch on any sample with 'clinically significant antibodies' (including Anti-D) if for no other reason than to eliminate 'wondering if there is anything else' and/or 'mistakes'.

 

Does anyone remember 'the old days' when we used to use a reagent containing Anti-D, -C, and -E (Anti-DCE) instead of just Anti-D?  Donor units that were positive with this mixture were labeled 'Rh-Pos' ... maybe we should go back to that practice.  Hmmm ... thoughts?

Ruling out with only heterozygous cells (with few exceptions, e.g. Anti-K) is risky business.  I don't allow my staff to do that and I don't recommend it.

• There are plenty of examples of antibodies that react with homozygous cells only (due to sensitivity of the test and concentration of the antibody) ... so you will get a negative result with heterozygous cells whether you run 1, 3 or 999 of them.
• Sure, if you miss such an antibody, it is weak and will likely not cause a noticeable 'reaction' ... you'll likely see it better next time around.  Oooor maybe you won't, some patients never pass that threshold and continue to react with only homozygous cells ... so you'll just keep wondering why the patient keeps coming back for more transfusions and perhaps rising chemistries, positive DAT, etc.

The 3+3 rule is often misinterpreted/simplfied.  In reality, we 'rule out' with 1 cell every time an antibody screen is deemed negative (e.g.. no antibody identification is performed, 2 more negative cells for each antigen is not sought, etc.).  This is ok as long as you are testing using homozygous cells for 'all', i.e. most 3-cell screening kits. 

 

As far as finding 'D-neg, C-pos and/or E-pos' reagent cells to determine if the Anti-D is masking Anti-C and/or Anti-E ... good luck!  Those are rare cells not seen often enough on panels.

 

Bottom line:  If patient is producing Anti-D (i.e. not passively acquired from a 'pure and only Anti-D' injection), we rule out Anti-C and/or Anti-E only if

a) we can locate the cells to do so ('never' happens)

or

the patient is positive for C and/or E respectively. 

If we cannot, the report is "Anti-D, Cannot rule out Anti-C and Anti-E" (whichever applies, most often they both apply). 

 

To address the original question:

Yes, we type Rh-neg (D-neg) RBCs for C and/or E as applicable.

Yes, we do perform an extended crossmatch on any sample with 'clinically significant antibodies' (including Anti-D) if for no other reason than to eliminate 'wondering if there is anything else' and/or 'mistakes'.

 

Does anyone remember 'the old days' when we used to use a reagent containing Anti-D, -C, and -E (Anti-DCE) instead of just Anti-D?  Donor units that were positive with this mixture were labeled 'Rh-Pos' ... maybe we should go back to that practice.  Hmmm ... thoughts?

While I agree with your statement about ruling out with 1 heterozygous cell is risky business, In this scenario, the risk is minimal.  If we were talking about Jka, that would be another story!

 

The fact that C and E will be absent on rh negative units at least 99% of the time and the unit is required to be crossmatch compatible through AHG mitigates whatever risk there might be.  Ruling out C and E with 1 r'r and r"r cell in the presence of Anti-D is time efficient, cost effective and safe.

 

The real issue here was the tech did not perform an AHG crossmatch.  That is a competency issue.

Can anyone please tell me where on the FDA website I should look to see if this is a reportable event?   

Can anyone please tell me where on the FDA website I should look to see if this is a reportable event?   

 

http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/BiologicalProductDeviations/ucm129721.htm#blcd

 

I think you could use this one:

 

RT-61-08 Compatibility {includes electronic or immediate spin crossmatch performed instead of full crossmatch, when required}.

Can anyone please tell me where on the FDA website I should look to see if this is a reportable event?   

This is the guidance document.  It's a little long but definitely a good resource to be familiar with.

 

http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/Blood/ucm073455.htm

 

There's a link at the top of the page to download the .pdf version.

 

If you head directly to

Section IV. EXAMPLES OF REPORTABLE AND NON-REPORTABLE EVENTS BY MANUFACTURING SYSTEM.

     D. Testing

           For transfusion services, reportable events may also include

 

This situation is actually used as an example of a reportable event. "Immediate spin crossmatch performed when a patient's history or testing requires an indirect antiglobulin test."

 

The reasion it says "may" is because if your procedures don't require an indirect antiglobulin crossmatch, then it's not reportable. I think most of the accrediting bodies do require the AHG crossmatch for history of antibody/positive antibody screens so this is more of a technicality.

Ruling out with only heterozygous cells (with few exceptions, e.g. Anti-K) is risky business.  I don't allow my staff to do that and I don't recommend it.

• There are plenty of examples of antibodies that react with homozygous cells only (due to sensitivity of the test and concentration of the antibody) ... so you will get a negative result with heterozygous cells whether you run 1, 3 or 999 of them.
• Sure, if you miss such an antibody, it is weak and will likely not cause a noticeable 'reaction' ... you'll likely see it better next time around.  Oooor maybe you won't, some patients never pass that threshold and continue to react with only homozygous cells ... so you'll just keep wondering why the patient keeps coming back for more transfusions and perhaps rising chemistries, positive DAT, etc.

The 3+3 rule is often misinterpreted/simplfied.  In reality, we 'rule out' with 1 cell every time an antibody screen is deemed negative (e.g.. no antibody identification is performed, 2 more negative cells for each antigen is not sought, etc.).  This is ok as long as you are testing using homozygous cells for 'all', i.e. most 3-cell screening kits. 

 

As far as finding 'D-neg, C-pos and/or E-pos' reagent cells to determine if the Anti-D is masking Anti-C and/or Anti-E ... good luck!  Those are rare cells not seen often enough on panels.

 

Bottom line:  If patient is producing Anti-D (i.e. not passively acquired from a 'pure and only Anti-D' injection), we rule out Anti-C and/or Anti-E only if

a) we can locate the cells to do so ('never' happens)

or

the patient is positive for C and/or E respectively. 

If we cannot, the report is "Anti-D, Cannot rule out Anti-C and Anti-E" (whichever applies, most often they both apply). 

 

To address the original question:

Yes, we type Rh-neg (D-neg) RBCs for C and/or E as applicable.

Yes, we do perform an extended crossmatch on any sample with 'clinically significant antibodies' (including Anti-D) if for no other reason than to eliminate 'wondering if there is anything else' and/or 'mistakes'.

 

Does anyone remember 'the old days' when we used to use a reagent containing Anti-D, -C, and -E (Anti-DCE) instead of just Anti-D?  Donor units that were positive with this mixture were labeled 'Rh-Pos' ... maybe we should go back to that practice.  Hmmm ... thoughts?

 

Where do you get sufficient supplies of r'r', r"r" ryr', ryr" or ryry cells to rule out anti-C and/or anti-E in the presence of anti-D?  Sometimes you just have to compromise, be pragmatic and use r'r and r"r.

 

As to the use of anti-D+C+E mixture coming back - over my dead body!  There were far too many instances of this being used on patients (including females of child bearing potential) who were r'r or r"r who were then given D+ blood and made anti-D.

In Sweden (work quoted in Race and Sanger)r"r 0.2254%, r"r" 0.0009%, r'r 0.3736%, r'r' 0.0024%, r'r" (or ryr) 0.0029%, and no figures for ryry. Of course, these frequencies will differ with different ethnic groups.

So E = 0.2292 & C = 0.3789 in D neg people by my calculations.

Although mathematics is amongst the many things that come under the heading of "not my strong point", yes!

Four (and a bit) years too late, but here is the Table to which I was referring in Rob Race and Ruth Sanger's Blood Groups in Man, 6th edition (and I hope that this does not land me in trouble with copyright laws!  Race and Sanger.pdf.

On ‎7‎/‎24‎/‎2013 at 10:24 PM, Mabel Adams said:

So E = 0.2292 & C = 0.3789 in D neg people by my calculations.

this frequency increases as it gets closer to the end of the shift and time to go home in my experience. 

On ‎7‎/‎22‎/‎2013 at 4:43 AM, Malcolm Needs said:

In Sweden (work quoted in Race and Sanger)r"r 0.2254%, r"r" 0.0009%, r'r 0.3736%, r'r' 0.0024%, r'r" (or ryr) 0.0029%, and no figures for ryry. Of course, these frequencies will differ with different ethnic groups.

From the fact book: the occurrence of haplotype r' (Ce) is 2% in all population groups listed (Caucasian, Black, Native Americans, Asians) haplotype r" (cE) is 1% Caucasian, 0% Black, 6% Native American,0% Asian and r_y (CE) is essentially 0% in all populations, of course that includes D+ populations.

r'r' and r"r" are rare across all populations. r'r is 0.8% occurrence for Caucasian, rare for Black, 0.1% for Asian.  r"r is 0.9% occurrence for Caucasian, rare for Black, rare for Asian. 

 

1 minute ago, DPruden said:

From the fact book: the occurrence of haplotype r' (Ce) is 2% in all population groups listed (Caucasian, Black, Native Americans, Asians) haplotype r" (cE) is 1% Caucasian, 0% Black, 6% Native American,0% Asian and r_y (CE) is essentially 0% in all populations, of course that includes D+ populations.

r'r' and r"r" are rare across all populations. r'r is 0.8% occurrence for Caucasian, rare for Black, 0.1% for Asian.  r"r is 0.9% occurrence for Caucasian, rare for Black, rare for Asian. 

 

Don't forget that these frequencies are complicated by the d(C)ce^S haplotype, found almost exclusively within the Black populations (and I KNOW d doesn't exist!).

I should have said, when I posted the table from Race and Sanger in this thread, that this was taken from their 1976 edition, and that, at the time, there were no monoclonal anti-D reagents, and phenotypes such as D^EL were unknown, and so the figures may have changed (but not by that much).