We had a nice little problem in over the past week.

It was a pregnant lady in her early 20's, who gave a forward result of 4+ with anti-A grouping reagent, 0 with anti-B grouping reagent, but with a 0 result with both A1 and B red cells against the lady's plasma.

All tests were carried out in DiaMed gel at, give or take, 22oC.

I can think of 4 explanations for this, but what do you think, and what further tests would you do?

I'll give you a few days (7?) to have a think.

:confused::confused::confused:

1) severely immunocompromised?

2) technical problem(human error)---forgot to add plasma???

1) severely immunocompromised?

2) technical problem(human error)---forgot to add plasma???

Well, I said I'd give it 7 days, but no, we did repeat the tests just in case of human error, and the results were the same.

:):)

I'll take a stab at one: Patient is a weak subgroup (perhaps ABm or ABel ??)

I'll take a stab at one: Patient is a weak subgroup (perhaps ABm or ABel ??)

You may be correct.

You may not be correct.

I'm not saying yet.

But, one thing I did ask was, what further tests would you do to prove/disprove your theory?

I COULD GET USED TO THIS FEELING OF POWER!!!!!!!!!!

:crazy::crazy:

To investigate the possibility of ABm or ABel:

1. See if the RBCs can absorb, then elute Anti-B. If they can, this would support the theory that a weak B antigen is present on the patient's cells.

2. If the patient is a secretor, check what soluble substances are present in his saliva. If he is a secretor, the presence of soluble A, B, and H substances in his salive would support the theory that pt is possibly ABm. (Only A & H substances would be secreted by an ABel individual.) (P.S. I do not know this info......I had to look it up!)

Well, that's about all I can offer.

Were you using serum rather than plasma? Serum may contain unusually potent anti-B that binds complement and interferes with agglutination. Try tube testing using plasma, or diluted patient plasma.

Weak Anti-B due to some reason (immunocomprised, bone marrow transplant, etc.). Get history. Do tube testing with 4 drops plasma rather than 2 and longer incubation. If you go below room temperature, make sure to include patient control.

Chimera - was she a twin? Could be a very small portion of B cells that prevented her from making anti-B. Get history, try adsorbing and eluting with Anti-B from group A donor.

Or maybe she has lived in sterile environment (bubble girl) all her life and not been exposed bacteria, etc to form ABO antibodies.

Okay, some of these are pretty far fetched!

Belva in Lincoln

Oooo.... Good answers, Belva!

I'm not saying anything more - yet!!!!!!!!!!!

:D:D:D:D

Hi Malcolm,

Like this one.

Having got the results you iterated, before I did any more testing, I would want a complete medical, previous pregnancy or transfusion history (including any signs of a transplacental loss from the foetus). Also how many weeks pregnant is she?

Give us this and I will have a stab at some answers.

Cheers,

Eoin

Hi Malcolm,

Like this one.

Having got the results you iterated, before I did any more testing, I would want a complete medical, previous pregnancy or transfusion history (including any signs of a transplacental loss from the foetus). Also how many weeks pregnant is she?

Give us this and I will have a stab at some answers.

Cheers,

Eoin

Hi Eoin,

She is early in pregnancy (nowhere near 28/40 yet).

One previous miscarriage.

No sign of FMH.

:)

I will try

1. A subgroup B

2..congenital anti-B deficient

3. potent anti-B

I just can remember this two explanation.

The further investigation is to extension the incubation time with human anti-B in 4 degree C and/ or adhesion and elution test to the B antigen. To test the saliva Blood group substances.

To prove the second explanation is to do the immunoglobulin Quantitative.

3. delute the serum to avoid Prozone phenomenon

Edited March 13, 201015 yr by shily

Hello Malcom I've read your "nice little problem" yesterday.

Por favor

could you wait until next week to give us the four explanations?

I would like to talk about it in my lab and then try to answer ...

Gracias

Hello Malcom I've read your "nice little problem" yesterday.

Por favor

could you wait until next week to give us the four explanations?

I would like to talk about it in my lab and then try to answer ...

Gracias

No problem, if everybody else is happy.

:confused::confused:

Malcolm,

If I am reading this right the patient forwards as an A but reverses as an O. The only unexpected reaction is the negative reaction for the Bcells in the reverse type. I have seen this happen before do to the specimen having been drawn above an active IV site and suffering the subsiquent contamination. At the bench, and in the absence of specimen contamination, however, I would try incubating at RT for x-time and depending on reactivity incubate further at 37C for x-time.

Edited March 14, 201015 yr by rravkin@aol.com

Malcolm,

If I am reading this right the patient forwards as an A but reverses as an O. The only unexpected reaction is the negative reaction for the Bcells in the reverse type. I have seen this happen before do to the specimen having been drawn above an active IV site and suffering the subsiquent contamination. At the bench, and in the absence of specimen contamination, however, I would try incubating at RT for x-time and depending on reactivity incubate further at 37C for x-time.

No, sorry.

The patient is grouping as a B, but the reverse group is that of an AB, rather than an O.

:o:o

It was a pregnant lady in her early 20's, who gave a forward result of 4+ with anti-A grouping reagent, 0 with anti-B grouping reagent, but with a 0 result with both A1 and B red cells against the lady's plasma.

OK Malcolm - now I'm REALLY confused. Is this lady forward-grouping as an A (as your first post would indicate) or as a B (as your last post would indicate)??

It was a pregnant lady in her early 20's, who gave a forward result of 4+ with anti-A grouping reagent, 0 with anti-B grouping reagent, but with a 0 result with both A1 and B red cells against the lady's plasma.

OK Malcolm - now I'm REALLY confused. Is this lady forward-grouping as an A (as your first post would indicate) or as a B (as your last post would indicate)??

Oh sorry Anna (and everybody else come to that).

The last post was a complete error. She is grouping as an A, and not as a B for the forward group.

I will write out 100 times,

"I MUST CHECK MY POSTS PROPERLY BEFORE I SUBMIT THEM."

Well spotted!

Mind you, of course, it does make the case just that little more difficult to work out when I give you duff information!!!!!!!!!!

:redface::redface:

Malcolm--did you repeat the ABO testing in gel or tube method? If we have ABO discrepancies, we repeat the test using the tube method, and if the backtype is weak, we incubate at room temp for about 15 minutes then re-centrifuge. Also, is there any transfusion history on the patient? Is she really a type AB and could have been transfused with type A cells, and that's what you're picking up on the front type?

Malcolm--did you repeat the ABO testing in gel or tube method? If we have ABO discrepancies, we repeat the test using the tube method, and if the backtype is weak, we incubate at room temp for about 15 minutes then re-centrifuge. Also, is there any transfusion history on the patient? Is she really a type AB and could have been transfused with type A cells, and that's what you're picking up on the front type?

Hi LisaM,

We repeated the testing in both gel and tube and got identical results.

More than that I cannot say as yet, except to say that the lady is healthy, so no recent transfusions.

:):)

Any other history on the patient, Malcolm? I found this:

http://www.ualberta.ca/~pletendr/tm-modules/abo/70abo-weakab.html

And since she's not a newborn or elderly, maybe #3 would apply if she has a hypogammaglobulinemia (maybe she's undiagnosed?)

Any other history on the patient, Malcolm? I found this:

http://www.ualberta.ca/~pletendr/tm-modules/abo/70abo-weakab.html

And since she's not a newborn or elderly, maybe #3 would apply if she has a hypogammaglobulinemia (maybe she's undiagnosed?)

I can't say anymore yet (see my earlier posts), otherwise I will start to give the game away.

That looks a really useful website, by the way.

Malcolm--here's another good webpage:

http://faculty.matcmadison.edu/mljensen/BloodBank/lectures/ABO%20discrepancies.htm

Very nice webpage, Lisa. Thanks!

Lisa, that is a nice webpage.

I had an outpatient OB patient in her first trimester who had reactions like this. Incubating the reverses at room temperature and 4C with an autocontrol didn't help. Absorbing and elujting with antisera and her cells yielded nothing. Had this been an inpatient I would have called the floor before doing all this testing to see if she were immunocompromised or had had a bone marrow transplant, but I just assumed an outpatient OB wouldn't have had a bone marrow transplant. When I finally called the physician's office for her history and explained the problem, they didn't have any information. A few minutes later they called me back, laughing, because they called the patient and she had had a bone marrow transplant in her teens and never bothered to tell her OB doctor.

Don't know it that is your problem, but it did teach me not to assume anything about patients and their problems..