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mollyredone

SIGNIFICANT ANTIBODIES FOR ELECTRONIC XM

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We are getting ready to start using electronic crossmatch with Meditech Magic 5.67.  My IT guy gave me an antibody dictionary page and you can select yes or no for significant, indicating that EXM would be appropriate or not.  As it stands in the dictionary now, there are more than a few that are listed as insignificant, such as M, N, Lea, Leb, P1, York and antibody of unknown significance/specificity.  And to be safe, since we don't antigen type for Lea, Leb, M or N, or identify an antibody which might be an HLA, we perform a gel XM.

Which antibodies do you routinely call insignificant that would be eligible for an electronic XM?

Also, does anyone have a procedure they would be willing to share?

TIA, Mari

Edited by mollyredone
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17 minutes ago, mollyredone said:

We are getting ready to start using electronic crossmatch with Meditech Magic 5.67.  My IT guy gave me an antibody dictionary page and you can select yes or no for significant, indicating that EXM would be appropriate or not.  As it stands in the dictionary now, there are more than a few that are listed as insignificant, such as M, N, Lea, Leb, P1, York and antibody of unknown significance/specificity.  And to be safe, since we don't antigen type for Lea, Leb, M or N, or identify an antibody which might be an HLA, we perform a gel XM.

Which antibodies do you routinely call insignificant that would be eligible for an electronic XM?

TIA, Mari

So, the easy questions first eh Mari?????!!!!!!!!!!!!!

Personally, I think the IT guy gave you a poisoned chalice.  The reason I say this is because we can all list antibodies that are not generally considered to be clinically significant, and then, all of a sudden, one comes along amongst these specificities that has not read the appropriate text books and goes ahead and causes a clinically significant reaction.  Then what happens is that the person who said "anti-X" is not clinically significant, and this single example of anti-X turns out to be clinically significant, and you have to defend this in court.

The real problem these days is that the technologies available to us are now much more sensitive than when I started (when cross-matches were recorded on a stone slab with a hammer and chisel) and many antibodies that were not clinically significant (because we just didn't detect them with the technologies available at the time) are now readily detectable - BUT, they are not necessarily detectable at strictly 37oC, as , for example, many examples of anti-M are now detected by "IAT", even though they do not really react (in real terms) at 37oC.  The real problem comes when, for example, an anti-M genuinely DOES react at 37oC, and it is treated as clinically insignificant, electronic issue is used, and one or more of the units is M+ and the patient has a severe reaction - who answers in court?

The worrying thing is that there have been papers published over the last few years quoting an anti-Leb as causing a transfusion reaction, and an anti-P1 causing a transfusion reaction (a certain Garratty G being a co-author on this one).

I would say, therefore, that the best thing to do is to read through the relevant parts of The Blood Group Antigen FactsBookHuman Blood Groups and Mollison's Blood Transfusion in Clinical Medicine (latest editions in each case), and use their experience, rather than your own (no insult intended) as the courts would probably take the authors as "experts" should you come across any of these clinically significant "outliers".

I wish you the very best of luck!

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Do you have a way of listing patients from your system who had incompatible crossmatches with antigen-negative units antigen-untyped units in the presence of a negative antibody screen?

Are you asking about patients whose current antibody screen is negative but have a history of antibody?  If so, the following antibodies are configured as clinically insignificant in our Meditech system when then allows electronic crossmatch: -Lea, -Leb, -M, -N, -P1, COLD, WARM, NAD, INC, -RhiG. 

In response to Malcom and on an individual basis, you could create an anti-M (M37)  that is clinically significant and an anti-M (M) that is clinically insignificant.

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Malcolm,

I agree!  I'm tempted to call all of them significant on my list except a cold or a passive D we named for residual Rhogam.  I do have the 3rd edition Blood Group Antigen Facts Book so I'll consult that as well.  I'll also use the info our reference lab puts on reports as a backup.

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14 hours ago, Dansket said:

If so, the following antibodies are configured as clinically insignificant in our Meditech system when then allows electronic crossmatch: -Lea, -Leb, -M, -N, -P1, COLD, WARM, NAD, INC, -RhiG. 

So you are saying that if you haven't determined the significance of an antibody (maybe and HLA or HTLA) that you would just perform an electronic XM?  And if you have determined that it is a warm auto with no underlying all antibodies that you would also perform an EXM?  That would take care of least incompatible!  What if the warm auto is showing anti-E or anti-e type specificity?  I'm including a list of all the antibodies in our Meditech dictionary-a little bit of overkill I think.

Antibody list.pdf

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I haven't seen any responses that address the issue of the current antibody screen status - negative or positive. It was my understanding that part of the Truth Table for Electronic XM should include a current antibody screen (irregardless of antibody history).  If the current screen is positive,  I don't believe the patient should qualify for electronic compatibility testing.

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1 hour ago, mollyredone said:

So you are saying that if you haven't determined the significance of an antibody (maybe and HLA or HTLA) that you would just perform an electronic XM?  And if you have determined that it is a warm auto with no underlying all antibodies that you would also perform an EXM?  That would take care of least incompatible!  What if the warm auto is showing anti-E or anti-e type specificity?  I'm including a list of all the antibodies in our Meditech dictionary-a little bit of overkill I think.

Antibody list.pdf

I agree with your antibody list.  Generally speaking, patient's with a negative antibody screen meet criteria for electronic crossmatch, excepting patient's with a history of clinically significant antibody.

Our policy states that if the patient's current antibody screen is positive, do serologic crossmatches (no exception).  If the current antibody screen is negative and the patient has a history of anti-Lea, -Leb, -P1, -M, -N, COLD, WARM (no specificity), NAD, INC, -RhiG, that patient qualifies for electronic crossmatch.  All other antibody specificities are considered clinically significant and require serologic crossmatching regardless of the current antibody screen test results.

Your future policy for electronic crossmatch could mirror your existing policy for immediate-spin crossmatch only.

Then I challenged you to review your facility's data to determine how many cases, if any, did serologic crossmatching detect a clinically significant antibody in a patient with a negative antibody screen.

Edited by Dansket
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NAD = A positive antibody screen and no agglutination observed in panel (all our testing is done in Gel on ProVue)

INC = A positive antibody screen and some but not all panel cells agglutinated with no apparent specificity

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For specimen requirements, do you require two ABO specimens drawn at separate times (could use a Heme specimen or even coag??) a retype of a sample by two different technologists or retype by same tech if sample drawn using a "mechanical barrier system or digital bedside patient identification system" (per CAP checklist), for which we have Mobilab.

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5 hours ago, applejw1 said:

I haven't seen any responses that address the issue of the current antibody screen status - negative or positive. It was my understanding that part of the Truth Table for Electronic XM should include a current antibody screen (irregardless of antibody history).  If the current screen is positive,  I don't believe the patient should qualify for electronic compatibility testing.

Agree with you.

We have set up criteria for EXM where it will only allow us to perform  if there is  no previous antibody screen positive and also current antibody screen MUST be negative regardless of clinical significant.  

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3 hours ago, mollyredone said:
3 hours ago, mollyredone said:

For specimen requirements, do you require two ABO specimens drawn at separate times (could use a Heme specimen or even coag??) a retype of a sample by two different technologists or retype by same tech if sample drawn using a "mechanical barrier system or digital bedside patient identification system" (per CAP checklist), for which we have Mobilab.

For specimen requirements, do you require two ABO specimens drawn at separate times (could use a Heme specimen or even coag??) a retype of a sample by two different technologists or retype by same tech if sample drawn using a "mechanical barrier system or digital bedside patient identification system" (per CAP checklist), for which we have Mobilab.

We don't have a "mechanical barrier system or digital bedside patient identification system".

For patients without a historical ABO on file, we test the uncentrifuged blood sample with Anti-A,B antiserum.  That test result is entered and filed in Meditech.  If the anti-A,B test is agglutinated, then Meditech reflexes the test CONFIRM which is ordered on a new specimen number that requires a second venipuncture.

Our BBK specimen collection labels are configured to view historical ABO on file and antibody identification on file without login and search in Meditech.

IMG_1141.JPG

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For consideration: 20 years ago in the dark ages I requested a variance from FDA to perform electronic compatibility tests. The BB system I was using had an excellent EC program.

I was told by FDA that EC was only for "pure" patients.  That meant that the screens had to be negative and NO antibodies, even clinically insignificant. I had to make a passive Anti-D significant before FDA would grant the variance.

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15 minutes ago, tricore said:

For consideration: 20 years ago in the dark ages I requested a variance from FDA to perform electronic compatibility tests. The BB system I was using had an excellent EC program.

I was told by FDA that EC was only for "pure" patients.  That meant that the screens had to be negative and NO antibodies, even clinically insignificant. I had to make a passive Anti-D significant before FDA would grant the variance.

I think that the FDA must either have been mistaken, or just plain wrong/ignorant (I'll leave others to decide which, and to, perhaps, guess my views on which best describes this decision).

If one performs sufficient "exquisite" serology on almost any person in the world, one will eventually detect, at the very least, a clinically insignificant auto-antibody and, probably, a clinically insignificant allo-antibody.  This would mean that almost nobody in the world would be eligible for electronic issue of blood, which is, self evidently, preposterous.

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It's interesting that you posted this because the supervisor and I reviewed our Meditech Antibody and Antigen dictionaries just recently. It hadn't been done in many years and whoever set it up previously configured antigen warnings and IAT XM for every antibody, so review/revision was a long time coming!

One difference from the discussion here that we decided upon was to retain the requirement of IAT XM for antibody of undetermined specificity (INC).

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27 minutes ago, goodchild said:

One difference from the discussion here that we decided upon was to retain the requirement of IAT XM for antibody of undetermined specificity (INC).

I simply could NOT agree more with you.  How on Earth can anyone say that an undetermined antibody specificity can be considered to be clinically insignificant?

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2 hours ago, goodchild said:

It's interesting that you posted this because the supervisor and I reviewed our Meditech Antibody and Antigen dictionaries just recently. It hadn't been done in many years and whoever set it up previously configured antigen warnings and IAT XM for every antibody, so review/revision was a long time coming!

So which antibodies do you have as insignificant and qualifying for an EXM?  And I agree on the INC as well.

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anti-D presumably due to RhIg, antibodies which fall into our bucket of "cold antibody", and Knops system/Ch/Rg/Cost antibodies. We may have another look at it before it's published to live and procedures updated.

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4 hours ago, Malcolm Needs said:

I simply could NOT agree more with you.  How on Earth can anyone say that an undetermined antibody specificity can be considered to be clinically insignificant?

Upon completion of initial testing with a conclusion of INC, samples are routinely sent to a reference laboratory.  If the reference laboratory concurs with our result, we enter INC in Meditech.  If the current antibody screen is negative and there is a historical antibody identification reported as INC, the patient qualifies for electronic crossmatch.

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9 hours ago, Dansket said:

Upon completion of initial testing with a conclusion of INC, samples are routinely sent to a reference laboratory.  If the reference laboratory concurs with our result, we enter INC in Meditech.  If the current antibody screen is negative and there is a historical antibody identification reported as INC, the patient qualifies for electronic crossmatch.

Ah  right.  Now I understand.

Thanks Dansket.

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20 hours ago, Dansket said:

Upon completion of initial testing with a conclusion of INC, samples are routinely sent to a reference laboratory.  If the reference laboratory concurs with our result, we enter INC in Meditech.  If the current antibody screen is negative and there is a historical antibody identification reported as INC, the patient qualifies for electronic crossmatch.

That makes sense to me as well, although we would rather save the patient (or hospital) money that would be spent on a reference workup and just do a gel crossmatch.  So I may make an M37 that's significant.

After skimming through the entire The Blood Group Antigen FactsBook  for transfusion reactions and HDFN, it is my decision that according to that book A1, DRHIG, Lea, Leb, Lua, M, N, Wrb, XGA and Yka are clinically insignificant, as well as cold auto, and warm auto without specificity once underlying allo-antibodies are ruled out and a negative screen.  Does that sound right?  We have a current warm auto patient in house with no underlying allo-antibodies and they recommend transfusion with E-, c-, K-,Fyb- and Jka- red cells.  Yikes! I should just order antigen negative units from the blood center, because otherwise I would have to screen 159 units to find 1 negative!  Maybe she will move out of state when she has recovered!

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16 minutes ago, mollyredone said:

After skimming through the entire The Blood Group Antigen FactsBook  for transfusion reactions and HDFN, it is my decision that according to that book A1, DRHIG, Lea, Leb, Lua, M, N, Wrb, XGA and Yka are clinically insignificant, as well as cold auto, and warm auto without specificity once underlying allo-antibodies are ruled out and a negative screen.  Does that sound right?  We have a current warm auto patient in house with no underlying allo-antibodies and they recommend transfusion with E-, c-, K-,Fyb- and Jka- red cells.  Yikes! I should just order antigen negative units from the blood center, because otherwise I would have to screen 159 units to find 1 negative!  Maybe she will move out of state when she has recovered!

I challenge you to find an allo-anti-Wrb mollyredone!!!!!!!!!!!!!!!!!!

As to your auto patient, I would advise transfusing R1R1, K- blood, unless or until they make an anti-Fyb and/or an anti-Jka.  The likelihood of them making these antibodies, with an impaired immune system is unlikely, but, if they do, THEN worry about them - not before, because, as you say, looking for a needle in a haystack, when the needle may be elsewhere, is very expensive.

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