incompatible CM

[lyla_n]

Female patient with negative DAT, Negative IAT, Negative antibody screen. Cross match by gel incompatible with two units of Packed cells out of a total of 5 units tested.

DAT and IAT of the incompatible units negative.

Patient scheduled for OLT.

Further course?? REason for incompatibility??

[Malcolm Needs ☆]

What is the patient's ABO group lyla_n?

[lyla_n]

AB+ve

[Malcolm Needs ☆]

AB+ve

Then there is a fair chance that what you have is an A2B, with an anti-A1. About 25% of A2B individuals produce an anti-A1.

The anti-A1 would not, of course, be detected in the screen, as you would be using group O red cells.

The chances are that the anti-A1 is not going to be clinically significant, as it is unlikely to react strictly at 37oC, so you could either cross-match strictly at 37oC (by tube, pre-warming the reactants before mixing and washing the IAT with warmed saline), or you could order A2 or A2B units from your supplier and cross-match those.

:comfort::comfort:

Edited December 1, 2010 by Malcolm Needs
Spelling - YET AGAIN!

[Liz]

The patient may have an antibody to a low incidence Antigen present on the donor's cells

The patient may be A2B with an anti-A1

The antigen to which the patient may have an antibody may have heterozygous expression on the sc cells and homozygous on the donors cells.

etc..

[Liz]

oouf... you got there a few seconds before me.

[Liz]

This is like my case scenario for students on the other thread !!!

[lyla_n]

But the forward grouping was done with Anti A1 lectin... THe group ws reported as A1B..

[Malcolm Needs ☆]

But the forward grouping was done with Anti A1 lectin... THe group ws reported as A1B..

Hmmm, that makes things a little more interesting - to say the least! WHat group were the units you cross-matched? Were they group AB or were they only ABO compatible?

[jayinsat]

But the forward grouping was done with Anti A1 lectin... THe group ws reported as A1B..

I'd say that suggests an antibody against a low frequency antigen. As far as transfusion goes, all crossmatches should be AHG compatible. You can try running a select cell panel of low frequency antigens if you have available cells to select. Keep us informed. I'd like to know the conclusion of the matter.

James

[Malcolm Needs ☆]

I'd say that suggests an antibody against a low frequency antigen. As far as transfusion goes, all crossmatches should be AHG compatible. You can try running a select cell panel of low frequency antigens if you have available cells to select. Keep us informed. I'd like to know the conclusion of the matter.

James

I can see from where you are coming, but 2 of 5 units being incompatible argues against this.

It is not more likely, perhaps, to be an antibody against something like the Co( antigen or either the Do(a) or Do( antigen, where these antigens are not expressed on the screening red cells?

[David Saikin]

Or it could just be an anti-IH/I or some such cold, nuisance ab. How strong were the rxs? Did they look like cold rxs in gel?

[jayinsat]

I can see from where you are coming, but 2 of 5 units being incompatible argues against this.

It is not more likely, perhaps, to be an antibody against something like the Co( antigen or either the Do(a) or Do( antigen, where these antigens are not expressed on the screening red cells?

I think I may be using improper terminology. I was considering anything thats not routinely on the screen cells and panels (Co(, Do, V, LuA etc) to be "low frequency". At least here in the states, on Ortho 0.8% panel A, these antigens are seldom included.

[Malcolm Needs ☆]

I think I may be using improper terminology. I was considering anything thats not routinely on the screen cells and panels (Co(, Do, V, LuA etc) to be "low frequency". At least here in the states, on Ortho 0.8% panel A, these antigens are seldom included.

Ah, fair comment.

I must admit, I did think you were talking about Wr(a) and other such antigens, but now I am clearer in what passes for my mind!

:peaceman::peaceman:

[Brenda K Hutson]

Frequency too high for Low Incidence (unless you are just a very unlucky person; don't buy a lottery ticket).

I have had a couple such scenarios. I see that you use GEL. I have seen a couple of problematic issues with GEL.

1.One time (at another place I worked), a Tech. performed an Antibody Screen on a patient with a history of some "unidentified antibody." This often meant something that reacted with only 1 cell; could not see a specificity; was not going to spend the time hunting down a Low Incidence. The Policy then was to perform coombs crossmatches "for compatibility;" keeping in mind that the frequency on the Antibody Screen/Panel should be roughly the same frequency you are seeing of incompatible crossmatches. The Antibody Screen that particular day was Negative (this was a historical antibody notation). Upon performing the coombs crossmatches, 2 of 3 were incompatible. Red Flag! That does not "make sense" with the Antibody Screen even though the patient has a history of "something" (something I keep emphasizing to my Techs.; things must make sense). So I told them to run a GEL Panel; even though the Screen had been Negative. The Panel demonstrated an Anti-Fyb. Fyb is known in the literature to sometimes be problematic with GEL.

So my first suggestion would be to go ahead and run a Panel, even though the Antibody Screen is Negative.

2. A second problem with GEL I have encountered numerous times in >1 Institution (as well as having such specimens submitted to the Refernce Lab I supervisors years ago) has to do with Jka Antibodies in GEL. Sometimes, not only does the Anti-Jka not hit any of the heterozygous cells (so dosage), but then not hitting all of the homozygous cells either. So even on a Panel, you may have all negative reactions with heterozygous Jka cells; and maybe only 1/2 of your Jka homozygous cells reacting. This is often missed because if people don't know this about GEL and Jka, they will probably rule-out the Jka on the their panel based on homozygous cells (though another thing I always teach staff is that once you perform your rule-outs and you have ruled everything out, take the reverse approach; look at your positive reactions and see if there is anything they all have in common. In this Jka scenario, you will find that all of the positive reactions are Jka homozygous cells (but the converse is not true; all homozygous Jka cells are not positive). You can then type the patient for Jka (if not transfused in past 3 months) to help confirm. Also, if you keep PEG around, give that a try; it will probably come up more clearly on the panel with that.

3. And my final thought: I don't know if you did this but I would also wash the donor red cell suspension prior to using the cells for the crossmatch.

Brenda Hutson, CLS(ASCP)SBB

Female patient with negative DAT, Negative IAT, Negative antibody screen. Cross match by gel incompatible with two units of Packed cells out of a total of 5 units tested.

DAT and IAT of the incompatible units negative.

Patient scheduled for OLT.

Further course?? REason for incompatibility??

[jcdayaz]

We have found in our facility that Jka suspected reactions that aren't following the rule books can sometimes work best in a Poly gel card...ie.IgG and C3d combined.

When are these pesky antibodies going to learn the rules?

[Ajac]

I had read somewhere that the Kidd antibodies were being missed (especially Jka) because often these are mixtures of IgM and IgG with the ones that fix complement almost always having an IgM portion. IgG Gel card matrix used to contain Dextran (not sure about now or not) causing IgM antibodies not to be picked up as much. The remaining IgG portion may or may not be enough to react with all Kidd + cells.

[Liz]

Well, Brenda that was very instructive, thank you for taking the time. Please continue to share your knowledge and experience as you do!

[Malcolm Needs ☆]

Well, Brenda that was very instructive, thank you for taking the time. Please continue to share your knowledge and experience as you do!

I agree; Brenda's posts, like some other peoples' posts, are always well-thought through, thoroughly educational and well-worth reading more than once to let the points made sink in.

:thanks::thanks:

[Brenda K Hutson]

Absolutely; that is what we are all here to do, right? Give and take...Unfortunately, I have not had much time lately to give.

Brenda

Well, Brenda that was very instructive, thank you for taking the time. Please continue to share your knowledge and experience as you do!

[Deny Morlino]

Thanks for the great post Brenda!

[Eoin]

Hi Guys,

Nice logical thought process Brenda - well worth a second read as Malcolm says.

Just a thought - have you tried enzyme treating a set of panel cells & then running coombs? - I remember running this in years past and it solved the problem - unfortunately I can't remember the antibody - old timers disease I think - or the cold is infiltrating the grey matter.

Cheers

Eoin

[Malcolm Needs ☆]

It was probably an antibody within the Kidd Blood Group System Eoin. This is undoubtedly the best way to detect them.

[lyla_n]

thanks pple...esp Brenda.. Did run a panel however nothing came up on that...

The units that we crossmatched were A1B pos..

May be Ab against some low incidence antigen..Dont have a rare Ag panel..

Got another request for one more unit, we cross matched 3 units expecting the worst but all 3 came compatible!!

[Malcolm Needs ☆]

Good for you lyla_n.

Your news tends to convince me even more that you have something like an anti-Cob, or even an anti-Lua, as the figures are about right.