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Wrong ABO typing by Gel


Jsbneg
Go to solution Solved by applejw,

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Hi all,

We had recently an ABO discrepancy on one of our patients (front typing  groupO; back typing  groupA) using the automated gel instrument Erytra (Grifols). When testing was done by tube method and manual gel (same manufacturer of gel cards and antisera reagents), the patient typed as straightforward group A (anti-A reacted strongly 4+ by both tube and manual gel methods). The same results were obtained again with a different sample collected from the patient. Testing on Erytra was repeated for first and second sample, again same results.  it goes without saying, all the daily QC of the gel cards on the instrument were fine and we had other patients that were typed corrected as groupA, except for the discrepant sample. The patient does not seem to have a subgroup of A (at least based on the results of tube and manual gel methods). I wonder if anyone else has had similar ABO discrepancies by gel. Thank you in advance.

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Was the patient recently transfused?  We had a situation several years ago where the patient sample results were one type on the Vision and another type in tube.  I learned that the instrument samples red cells from the bottom of the patient specimen which, after centrifugation, is where the majority of the more dense transfused cells are vs. the top of the red cell layer where the less dense autologous red cells are.   This cause for a forward typing discrepancy was confirmed after communications with Ortho.

The theory was confirmed with manual gel testing where red cells were sampled from the top, middle and bottom of the red cell layer of the patient's specimen. The top layer of red cells were Group O, the middle and bottom were primarily Group A.  This patient was discovered to be Group O after receiving several Group A RBC transfusions.  The reverse typing showed reactivity only with Group B red cells at that time.

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11 hours ago, jayinsat said:

That is quite concerning. Have you found a resolution? You may want to contact technical support and refer this to them. There is a significant issue going on. They will probably want samples to see if they can reproduce it on their end.

Quite concerning indeed. Luckily the mistyping is from groupA to groupO....We did contact Grifols technical support and provided all the results and lot numbers. We haven't gotten an explanation yet from their end.

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8 hours ago, Malcolm Needs said:

Would you be able to disclose the underlying pathology of the patient please?

The patient was admitted into our ER for severe anemia likely due to GI bleed. His HgB was 3.7 g/dL when admitted. Received 3 emergency Opos RBCs units. The type and screen on Erytra was performed after the transfusion of the first 3 units.

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8 hours ago, applejw said:

Was the patient recently transfused?  We had a situation several years ago where the patient sample results were one type on the Vision and another type in tube.  I learned that the instrument samples red cells from the bottom of the patient specimen which, after centrifugation, is where the majority of the more dense transfused cells are vs. the top of the red cell layer where the less dense autologous red cells are.   This cause for a forward typing discrepancy was confirmed after communications with Ortho.

The theory was confirmed with manual gel testing where red cells were sampled from the top, middle and bottom of the red cell layer of the patient's specimen. The top layer of red cells were Group O, the middle and bottom were primarily Group A.  This patient was discovered to be Group O after receiving several Group A RBC transfusions.  The reverse typing showed reactivity only with Group B red cells at that time.

This is very interesting. The patient was in fact transfused 3 uncrossmatched groupO RBC units before the T&S testing was performed His baseline Hgb was very low (3.7g/dL). I will investigate this by repeating the manual gel testing using the upper RBC layer. Thank you.

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10 hours ago, Jsbneg said:

The patient was admitted into our ER for severe anemia likely due to GI bleed. His HgB was 3.7 g/dL when admitted. Received 3 emergency Opos RBCs units. The type and screen on Erytra was performed after the transfusion of the first 3 units.

Well, that's got rid of two of my possible theories in one fell swoop!

I was wondering either about loss of antigenicity due to some form of myeloid malignancy, or of adsorption of autologous secreted A substance on to the  donor group O red cell surface following a successful BMT or stem cell transplant, which may be seen with only some clones of anti-A (see, for example, Cripps K, Mullanfiroze K, Hill A, Moss R, Kricke S.  Prevalence of adsorbed A antigen onto donor-derived group O red cells in children following stem cell transplantation: A single-centre evaluation.  Vox Sang 2023; 118: 153-159.  DOI.10.1111/vox.13386., but I saw this phenomenon in adults many times when working at Westminster Hospital).

Oh well, back to having more thoughts!

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12 hours ago, Jsbneg said:

This is very interesting. The patient was in fact transfused 3 uncrossmatched groupO RBC units before the T&S testing was performed His baseline Hgb was very low (3.7g/dL). I will investigate this by repeating the manual gel testing using the upper RBC layer. Thank you.

I strongly suspect that you've got your answer. Echo/Lumena probes are calibrated to go to a specific depth after level sensing at the top of the plasma of the specimen and I would think that is true for other analyzers as well. Another (opposite) problem that can happen is failure to pick up a red cell sample if the Hct is extremely low. With the 'extra' plasma in the tube because of the low Hct, the probe doesn't go deep enough after level sensing the specimen to reach the red cells.

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The most likely answer has been given above: newly formed autologous red cells have a lower gravity than transfused cells and will concentrate at the top of the re cell pellet whereas transfused cells will seat at the bottom. I hereby attach a paper describing that phenomenon. I hope Grifols will thank you for giving them the answer :-)     20230301142735376.pdf20230301142735376.pdf

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1 hour ago, Arno said:

The most likely answer has been given above: newly formed autologous red cells have a lower gravity than transfused cells and will concentrate at the top of the re cell pellet whereas transfused cells will seat at the bottom. I hereby attach a paper describing that phenomenon. I hope Grifols will thank you for giving them the answer :-)     20230301142735376.pdf20230301142735376.pdf

Thanks for this explanation Arno.  I should have thought of it myself (but didn't!) as my friend Bill Chaffe, a former President of the BBTS described just such a situation in a meeting a few years back.

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Well, the transfusion history was an important piece of this puzzle. I see this all the time on the ECHO Lumena. When a patient has more donor cells (group O) than autologous cells, the ECHO will often give a ? because of the mixed field reaction. When looking at the images, it looks like a clear 3+ or stronger. Tube is usually 4+ with mixed field. I should have asked transfusion history from the beginning. 

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Thank you all so much for your explanations. I agree with jayinsat regarding the importance of transfusion history in this case, but I would have expected mixed field on the instrument, which was not the case. The concept of the density difference between the autologous RBCs vs the transfused RBCs and its impact on the probe sampling is very fascinating. Thank you all for sharing the papers that explain this phenomenon.

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16 hours ago, mimi03 said:

Jsbneg,

 

Am I missing something. You said the patient was truly a type O after receiving several type A RBC's. Maybe I'm missing something in the message

Hi mimi03,

Sorry if I didn't make it clear. it was actually the opposite of what you said. The patient was truly group A, but after receiving 3 units of group O RBCs (as emergency) , the front ABO type on Erytra was coming out as group O on multiple runs post transfusion, while the same samples were correctly typed as group A by tube testing and manual gel. The explanation of this phenomenon was provided above :)

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On 3/2/2023 at 5:17 AM, RichU said:

The same phenomenon is seen if you use a spun sample for DATs.

The cells at the top can be negative and the ones from the bottom positive if recently transfused.

Also, fetal bleed screen testing on a spun sample.  Those giant fetal cells will be on top.  Mix well before testing!

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  • 2 weeks later...
On 3/12/2023 at 5:22 PM, mpmiola said:

I'm curious to know what the conclusion from the company Grifols is, let us know if you can.

Hi mpmiola,

I apologize for my late reply.

Grifols just confirmed the phenomenon that was described in the discussion above as the cause of the ABO discrepancy. They stated that the probe in Erytra analyzer goes down to 2mm from the bottom of the tube to pick up red cells. in this case, the transfused cells (group O) are more heavier (more dense) than the patient's own cells (group A) and therefore they occupied the bottom of the tube after centrifugation.  Since the probe only takes cells from the bottom of the tube, it only picked up the transfused cells (group O).

Hope this makes it  clear to everyone.

 

 

 

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On 3/17/2023 at 3:41 PM, Mabel Adams said:

I think the transfused cells were at the bottom rather than the top.  The analyzer samples from the bottom, I think.

That is correct Mabel Adams. Thank you for clarifying that. Transfused cells are more heavier that autologous cells, and therefore they reside at the bottom of tube after centrifugation. The probe in Erytra analyzer picks up the cells 2mm from the bottom of the tube.

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13 hours ago, Jsbneg said:

Hi mpmiola,

I apologize for my late reply.

Grifols just confirmed the phenomenon that was described in the discussion above as the cause of the ABO discrepancy. They stated that the probe in Erytra analyzer goes down to 2mm from the bottom of the tube to pick up red cells. in this case, the transfused cells (group O) are more heavier (more dense) than the patient's own cells (group A) and therefore they occupied the bottom of the tube after centrifugation.  Since the probe only takes cells from the bottom of the tube, it only picked up the transfused cells (group O).

Hope this makes it  clear to everyone.

Thanks for your return.
I'm glad they took on this condition.
However, I hope they are looking at ways to minimize this risk of ABO phenotyping failure, especially with recipient samples. Alternatives must exist, such as decreasing sample centrifugation time or speed...

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