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Posts posted by SbbPerson
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56 minutes ago, yan xia said:
or there are unexpected antibody/antibodies in the patient's plasma.
That is what we are trying to figure out. Thank you
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20 minutes ago, Malcolm Needs said:
Looks like it could be an Oh individual.
Try testing the red cells of the patient with Ulex europeaus.
Result:
Patient red cells + Ulex europepeaus = Negative
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We got a blood sample for ABO/Rh and Antibody screen testing.
Results:
Forward typing:
Anti- A : Negative
Anti-B : Negative
Reverse typing:
A1 cells: 4+
B cells: 4+
Antibody screen and auto-control:
Cell 1: 4+
Cell 2: 4+
Cell 3: 4+
Auto-control: Negative
Patient is from Mumbai.
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On 6/27/2016 at 7:58 AM, amym1586 said:
I've always wondered about the women who have gotten RHIG at 28 weeks and it not show up at all in Gel at delivery.
Is it possible that all the RhIg was neutralized by RH positive red cells?
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22 minutes ago, Malcolm Needs said:
That is true, but then they need to follow the pregnancy by other means, such as ultrasound and/or mid-cerebral artery Doppler measurements are performed to ensure the health, or otherwise of the foetus is followed.
Yes, I am sure they probably order those other tests you mention. But the topic of this thread is on "why titers are not ordered on subsequent pregnancies".
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22 hours ago, L.C.H. said:
If the antibody is no longer present in this pregnancy, then so far, so good! but some antibodies can wax and wane, and if this fetus is positive for an 'offensive' antigen, that antibody may start kicking up again in mom during the pregnancy. If you know which antibody caused it last time, you can look up and see if it is one that tends to wax and wane.
Personally, I'd be concerned that the mom you describe could have HDFN again with this current fetus if the fetus has the offending antigen and mom's immune system catches wind of it. I am unclear on the recommendation that titering would only be done with the first pregnancy - our titer levels are what trigger OBs to order Dopplers for fetal anemia, so I don't know how titers could just be passed over simply b/c it's a different pregnancy. We often see the same woman come back across years with multiple pregnancies, and yes, if we find a clinically significant antibody, we do start chasing titers, regardless of whether she has ad the antibody in the past.
Some mother titers remain high during subsequent pregnancies. Clinical information from the titers would then be misleading. This is why doctors don't order titers on moms who has been sensitized from the first pregnancies.
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On 4/20/2020 at 7:41 AM, galvania said:
It depends a bit on how you work. If you are working manually then it is quite common to pipette a whole series of tests . In this time the cells can cool down enough for the anti-M to latch on, and once it's on it stays on. On the other hand, panels tend to go up individually so the cells stay warmer
I am sorry for so many questions. You said the panels tend "to go up individually". What do you mean by that "go up individually"? Can you elaborate more on that? Individually, like by cell#? Thank you .
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On 7/3/2018 at 9:35 PM, sahar zaid said:
Just looking for any help for taking the BB Exam. anyone here who has taken it recently.
Thanks for the help!
I am taking the SBB exam this summer. Hopefully, things would be calm down a bit by then and I would be able to take it. Can I ask you, how did you do in your BB Exam? Thank you.
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On 4/29/2020 at 9:29 AM, galvania said:
Because I've seen so many of them………….
But actually if your panel is not in the same buffer then pH or ionic strength could be the culprit rather than the temperature.
Important to stress that these cold anti-Ms (in that they dont react strictly at 37°C) have no clinical significance.
If it happens again, you can try the following:
1. Repeat the panel, incubating for 15mins at RT (on a Coombs card). The results will be stronger in this case.
AND 2. Repeat the screen in the following way. Warm the cells to 37°C (best just to use a small aliquot - you dont want to 'cook' the whole bottle). And put the Coombs card (foil still on) in the incubator for 15mins. Put the patient's plasma in the incubator. IN the incubator, pipette 50ul of cells into the appropriate wells followed by the patient's plasma. Incubate for 15mins. At the same time, start the centrifuge empty. This warms the centrifuge up a bit. After 15mins put the incubated card into the centrifuge which will have now stopped and centrifuge immediately.
This should negativise the screen results. This is about the nearest you can get to doing a gel test at strictly 37°C
Thank you very much. This have been very helpful. I am sorry, I just have another question. You said you have seen so many of them. What was the cause for majority of those cases you encountered? What was the typical/common reason?
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On 1/23/2018 at 6:24 PM, Jermin said:
Hi All,
I was wondering if antibody titre is performed on a pregnant mother who previously had HDFN. According to the books, it mentions 'After the first affected pregnancy, the antibody titer is no longer useful'. Therefore does it mean that it doesn't matter what the antibody titre level is, and should be referred to fetal medicine specialist regardless? Or if there is more to this, I would be grateful for some enlightenment
After some mothers are sensitized, their titers can be consistently high during subsequent pregnancies. In some case, even when the baby is Rh positive or Rh negative. The titer in this cases would be not helpful for the doctor to develop a treatment plan for the patient.
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5 hours ago, galvania said:
It depends a bit on how you work. If you are working manually then it is quite common to pipette a whole series of tests . In this time the cells can cool down enough for the anti-M to latch on, and once it's on it stays on. On the other hand, panels tend to go up individually so the cells stay warmer
I am sorry, but what do you mean by the "panels tend to go up individually"? We just have 2 panels, and both these panels have about 20 cells. So about 40 cells of varying phenotypes.
In your original post, you said the "main culprit here is Anti-M". You were right! How did you know exactly?
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On 4/17/2020 at 7:45 AM, Arno said:
In addition to what has been nicely explained by Malcolm, it could be as well an example of Sd(a++) cell (commonly named "super Sid") reacting with a weak anti-Sda. The Sda antigen is not a LFA (expressed on more than 90% of cells) though some cells "overexpresse" it.
Anti-Sda usually gives weak/DP reactions and can be neutralized using urine (contains soluble Sda substances).
Other weak antibodies may behave the same way, e.g. anti-P1 reacting against "strong P1" cells only.
However, that does not change at all what Malcolm said "I wouldn't expend too much time or energy trying to sort out the exact specificity. In all cases of such an antibody, as long as you cross-match by the same method as you used in detecting the presence of the antibody in the first place, it would be quite safe to give cross-match compatible blood."
Thank you for replying. Everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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On 4/17/2020 at 9:20 AM, David Saikin said:
It is a long shot. I don't think I've ever seen a Jsa+ screening cell.
Plus - it would be nice to know how strong the reaction(s) was and which cell(s) was reacting.
Thank you for replying. Everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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On 4/17/2020 at 8:08 AM, John C. Staley said:
I'm with exlimey, please clarify what you mean by positive antibody screen. One cell positive or all cells positive or something in between.
Thank you for replying. Everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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On 4/17/2020 at 6:46 AM, exlimey said:
All screening cells reactive, or some other pattern ?
Thank you for replying. Everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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On 4/17/2020 at 5:55 AM, Malcolm Needs said:
It sounds remarkably like one of your screening cells is expressing a low prevalence antigen that is not expressed on your panel cells.
Antibodies directed against low prevalence antigens are actually quite common, but they are rarely detected because red cells expressing the cognate antigen are so rare.
I wouldn't expend too much time or energy trying to sort out the exact specificity. In all cases of such an antibody, as long as you cross-match by the same method as you used in detecting the presence of the antibody in the first place, it would be quite safe to give cross-match compatible blood.
The other thing is that the screening cell may be expressing an HLA antigen. You could treat the cell with chloroquine, and that will get rid of the HLA antigen.
Thank you for replying. Everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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5 hours ago, galvania said:
It depends a bit on how you work. If you are working manually then it is quite common to pipette a whole series of tests . In this time the cells can cool down enough for the anti-M to latch on, and once it's on it stays on. On the other hand, panels tend to go up individually so the cells stay warmer
Thank you for replying. Actually everything was done by gel card, we don't use the tube method. Patient was typed A Pos. The antibody screen was 1+ positive on Screening cell 1 and 3, negative on Screening cell 2. But when we did the Antibody Identification panel and Auto control , they were all negative. We repeated everything and got the same results. We redrew the patient for a new specimen and got the same results.
We sent out the specimen for an Antibody Identification at a reference lab. The result we got back was Anti-M.
I am just wondering, why didn't our panels picked this up? Why only the screening cells were positive? What was the reasoning behind this? The panel and all our reagents have passed QC and are not expired. There was no signs of contamination in our specimen or reagents. Thank you.
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On 9/6/2015 at 2:12 AM, galvania said:
there are three main reasons why this can happen:
1. antibody against a low frequency antigen present on the screening cell but not on the panel
2. Temperature difference between the screen and the panel. Main culprit here is anti-M
3. contamination
Are there lots of screens positive with this cell? Yes, all in a batch - cell contaminated
No, only this one, but neg on repeat - either 2 or 3
Some - either 1 or 2
You can repeat the panel in IAT (I presume we are talking about an IAT technique here) at RT. If it's an anti-M it will come out more strongly
If it's an anti-LFA then finding blood that is XM-compatible won't be a problem
On number 2, you said there was a temperature difference between screen and panel. What did you mean by that? Both screen and panel were performed by Gel cards and incubated at 37 degrees C for 15 minutes.
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Can anyone tell me what is going on here and why?
Okay, I got a type and screen ordered on a specimen. We did the type , and the patient was A Pos. The antibody screen was positive. Then we did an antibody identification panel, it was all negative, including the auto-control it was also negative. All typing, Ab screen, Ab panel, and auto-control was performed by gel cards.
What is going on here and how can we solve it? Thank you.
What is the meaning of this?
in Transfusion Services
Posted
Result:
Antibody identification panel:
All panel cells = 4+
Auto-Control= Negative