Malcolm Needs

I just answered this question.

My Score PASS  

The simple answer is gagpinks, but this is the answer I have just received from my friend at the IBGRL (who shall remain anonymous for now).

The question I put was as follows:

"Sorry to bother you yet again, but I have had a query from a friend. I think I know the answer, but I wanted to check with an expert. If a pregnant lady has an allo-anti-D, can this affect cffDNA harvesting from the mother's circulation? I don't think it does unless the anti-D knocks out all of the foetal red cells. Best wishes from this bloody nuisance, Malcolm"
Answer below.

"Hi, that's right, anti-D makes no difference to the cffDNA test. The two biggest problems are false negatives due to insufficient RHD gene in the test sample and mums with a RHD gene (despite pheno typing as D-) leading to strong positive results. Take it easy."

As I said, the friend will remain anonymous for now, but, suffice it to say, he/she is one of the people who do the test, so I think the answer can be trusted!
 

The simple answer is gagpinks, but this is the answer I have just received from my friend at the IBGRL (who shall remain anonymous for now).

The question I put was as follows:

"Sorry to bother you yet again, but I have had a query from a friend. I think I know the answer, but I wanted to check with an expert. If a pregnant lady has an allo-anti-D, can this affect cffDNA harvesting from the mother's circulation? I don't think it does unless the anti-D knocks out all of the foetal red cells. Best wishes from this bloody nuisance, Malcolm"
Answer below.

"Hi, that's right, anti-D makes no difference to the cffDNA test. The two biggest problems are false negatives due to insufficient RHD gene in the test sample and mums with a RHD gene (despite pheno typing as D-) leading to strong positive results. Take it easy."

As I said, the friend will remain anonymous for now, but, suffice it to say, he/she is one of the people who do the test, so I think the answer can be trusted!
 

The simple answer is gagpinks, but this is the answer I have just received from my friend at the IBGRL (who shall remain anonymous for now).

The question I put was as follows:

"Sorry to bother you yet again, but I have had a query from a friend. I think I know the answer, but I wanted to check with an expert. If a pregnant lady has an allo-anti-D, can this affect cffDNA harvesting from the mother's circulation? I don't think it does unless the anti-D knocks out all of the foetal red cells. Best wishes from this bloody nuisance, Malcolm"
Answer below.

"Hi, that's right, anti-D makes no difference to the cffDNA test. The two biggest problems are false negatives due to insufficient RHD gene in the test sample and mums with a RHD gene (despite pheno typing as D-) leading to strong positive results. Take it easy."

As I said, the friend will remain anonymous for now, but, suffice it to say, he/she is one of the people who do the test, so I think the answer can be trusted!
 

The simple answer is gagpinks, but this is the answer I have just received from my friend at the IBGRL (who shall remain anonymous for now).

The question I put was as follows:

"Sorry to bother you yet again, but I have had a query from a friend. I think I know the answer, but I wanted to check with an expert. If a pregnant lady has an allo-anti-D, can this affect cffDNA harvesting from the mother's circulation? I don't think it does unless the anti-D knocks out all of the foetal red cells. Best wishes from this bloody nuisance, Malcolm"
Answer below.

"Hi, that's right, anti-D makes no difference to the cffDNA test. The two biggest problems are false negatives due to insufficient RHD gene in the test sample and mums with a RHD gene (despite pheno typing as D-) leading to strong positive results. Take it easy."

As I said, the friend will remain anonymous for now, but, suffice it to say, he/she is one of the people who do the test, so I think the answer can be trusted!
 

Thanks Malcolm.  
I checked it she was not given large dose of anti -D in her first pregnancy.   However in her first pregnancy she developed anti D at 32 weeks where her level was 0.5Iu/ml then at end of her first pregnancy level was 1.0IU/ml. 
As per routine antenatal sample if booking blood is Rh negative we send sample for FDS for Rh D prediction. 
Could it be because lady had Allo antiD? When lady has Allo anti D do they use different techniques? 
 
 

Yes.  
Another thought do you think in 1st pregnancy anti-D could be in IgM nature and therefore level might  be slightly raised? 
 

Agreed, sounds like you're moving to a less secure option for whatever reasons, so in that case I say go low tech and put a physical lock on the fridge door. Helmer sells fridges that have built in electronic access control, but you can also drill right through the handle bit and get a combo lock put on it. No access unless they call BB for the combo..... there are definitely ways to secure this low cost, I've got experience with both of these options and they work just fine after the surgeons stop complaining about it.  

I have a little bit more info on my case. In July she had a T&S done and the ABID was neg. She came through our ER as an MVA patient.  We use Capture R method (Echo) All panels show a perfect Jka. The throw off is the Complement is w+ after 5 min incubation. she antigen typed Jka+. Is this a true Jka or possible auto-Jka or varient. Patient was discharged same day. So no extra samples can be collected for send-off to reference lab. Our hospital does not handle OBGYN patients. 

I would most strongly advise you to send a sample, possibly even multiple samples throughout the pregnancy, to a Reference Laboratory.

As the patient is pregnant, there is the possibility that the Jk(a) antigen you are detecting is actually being expressed on the red cells of the foetus, and you are detecting it as a result of a foeto-maternal haemorrhage.  However, the Jk(a) antigen is not necessarily straight forward, as there are weakened forms of the antigen (and the Jk(b) antigen come to that) where there are amino acid substitutions remote from the site usually associated with the Jk(a) and Jk(b) antigens (280 of the mature protein).
In addition though, you have, obviously, to consider the health of the unborn baby who, even if the antibody does turn out to be a maternal auto-anti-Jka, may cause haemolytic disease of the foetus and newborn, albeit this will usually be be very mild.
I attach a PowerPoint which may, or may not help you in your decision to send a sample to your local Reference Laboratory (also tell them the ethnicity of the patient).
 
Interesting case - please keep us informed.
In Depth Lecture on The Kidd Blood Group System.pptx

I would most strongly advise you to send a sample, possibly even multiple samples throughout the pregnancy, to a Reference Laboratory.

As the patient is pregnant, there is the possibility that the Jk(a) antigen you are detecting is actually being expressed on the red cells of the foetus, and you are detecting it as a result of a foeto-maternal haemorrhage.  However, the Jk(a) antigen is not necessarily straight forward, as there are weakened forms of the antigen (and the Jk(b) antigen come to that) where there are amino acid substitutions remote from the site usually associated with the Jk(a) and Jk(b) antigens (280 of the mature protein).
In addition though, you have, obviously, to consider the health of the unborn baby who, even if the antibody does turn out to be a maternal auto-anti-Jka, may cause haemolytic disease of the foetus and newborn, albeit this will usually be be very mild.
I attach a PowerPoint which may, or may not help you in your decision to send a sample to your local Reference Laboratory (also tell them the ethnicity of the patient).
 
Interesting case - please keep us informed.
In Depth Lecture on The Kidd Blood Group System.pptx

I would definitely refer this patient's sample to a reference lab for JK sequencing. As my friend Malcolm mentioned above, variants of JK antigens are not uncommon. The most common variant I've seen is caused by c.130G>C, which causes weakened expression of the Jka antigen. Interestingly, some patients with this variant would make anti-Jka, but I don't think we know much about the clinical significance of this antibody.

I would most strongly advise you to send a sample, possibly even multiple samples throughout the pregnancy, to a Reference Laboratory.

As the patient is pregnant, there is the possibility that the Jk(a) antigen you are detecting is actually being expressed on the red cells of the foetus, and you are detecting it as a result of a foeto-maternal haemorrhage.  However, the Jk(a) antigen is not necessarily straight forward, as there are weakened forms of the antigen (and the Jk(b) antigen come to that) where there are amino acid substitutions remote from the site usually associated with the Jk(a) and Jk(b) antigens (280 of the mature protein).
In addition though, you have, obviously, to consider the health of the unborn baby who, even if the antibody does turn out to be a maternal auto-anti-Jka, may cause haemolytic disease of the foetus and newborn, albeit this will usually be be very mild.
I attach a PowerPoint which may, or may not help you in your decision to send a sample to your local Reference Laboratory (also tell them the ethnicity of the patient).
 
Interesting case - please keep us informed.
In Depth Lecture on The Kidd Blood Group System.pptx

I would most strongly advise you to send a sample, possibly even multiple samples throughout the pregnancy, to a Reference Laboratory.

As the patient is pregnant, there is the possibility that the Jk(a) antigen you are detecting is actually being expressed on the red cells of the foetus, and you are detecting it as a result of a foeto-maternal haemorrhage.  However, the Jk(a) antigen is not necessarily straight forward, as there are weakened forms of the antigen (and the Jk(b) antigen come to that) where there are amino acid substitutions remote from the site usually associated with the Jk(a) and Jk(b) antigens (280 of the mature protein).
In addition though, you have, obviously, to consider the health of the unborn baby who, even if the antibody does turn out to be a maternal auto-anti-Jka, may cause haemolytic disease of the foetus and newborn, albeit this will usually be be very mild.
I attach a PowerPoint which may, or may not help you in your decision to send a sample to your local Reference Laboratory (also tell them the ethnicity of the patient).
 
Interesting case - please keep us informed.
In Depth Lecture on The Kidd Blood Group System.pptx

I would most strongly advise you to send a sample, possibly even multiple samples throughout the pregnancy, to a Reference Laboratory.

As the patient is pregnant, there is the possibility that the Jk(a) antigen you are detecting is actually being expressed on the red cells of the foetus, and you are detecting it as a result of a foeto-maternal haemorrhage.  However, the Jk(a) antigen is not necessarily straight forward, as there are weakened forms of the antigen (and the Jk(b) antigen come to that) where there are amino acid substitutions remote from the site usually associated with the Jk(a) and Jk(b) antigens (280 of the mature protein).
In addition though, you have, obviously, to consider the health of the unborn baby who, even if the antibody does turn out to be a maternal auto-anti-Jka, may cause haemolytic disease of the foetus and newborn, albeit this will usually be be very mild.
I attach a PowerPoint which may, or may not help you in your decision to send a sample to your local Reference Laboratory (also tell them the ethnicity of the patient).
 
Interesting case - please keep us informed.
In Depth Lecture on The Kidd Blood Group System.pptx

It sounds to me like you are doing everything that you should do, without either over-shaking the tube, or over-reading the contents.

I am extremely glad that you are not using a microscope, as, if you did, you would almost certainly see the odd couple of red cells "kissing each other", even if they have been incubated in isotonic saline.

The other thing is (and I speak with some 43 years of working in blood group serology) if the reactions in the tube are THAT weak, the chances of any atypical alloantibody that you might miss being clinically significant are absolutely minute.

If you are still worried, however, get a more experienced worker to read your tests as well, until you feel confident.  That is how I learned when I started.
I wish you the best of luck in your future career.

I don't know, although I have heard rumours.

I'll contact Martin Olsson via Jill Storry, but you'll have to give me a couple of days.

A few references you might find of interest:
Management of Blood Donors and Blood Donations From Individuals Found to Have a Positive Direct Antiglobulin Test. Transfusion Medicine Reviews 2012. Volume 26, Issue 2,  Pages 142-152,
Garratty G. The significance of IgG on red cell surface. Transfus Med Rev. 1987;1:47–57.
Petz LD, Garratty G. Immune Haemolytic Anaemias. 2nd ed. Philadelphia, PA: Churchill Livingstone; 2004.

Welcome to this wonderful site kjmiller.

thank you very much 

Not she, but it's possible the person that conveyed it to me got it from Dr. Worlledge.

It sounds to me like you are doing everything that you should do, without either over-shaking the tube, or over-reading the contents.

I am extremely glad that you are not using a microscope, as, if you did, you would almost certainly see the odd couple of red cells "kissing each other", even if they have been incubated in isotonic saline.

The other thing is (and I speak with some 43 years of working in blood group serology) if the reactions in the tube are THAT weak, the chances of any atypical alloantibody that you might miss being clinically significant are absolutely minute.

If you are still worried, however, get a more experienced worker to read your tests as well, until you feel confident.  That is how I learned when I started.
I wish you the best of luck in your future career.

Wow , thanks everyone!!! Such great advice! I am so grateful for all the tips. They are all really helpful!!!

My motto was "when in doubt, shake it out".  Seemed to work for me.

It sounds to me like you are doing everything that you should do, without either over-shaking the tube, or over-reading the contents.

I am extremely glad that you are not using a microscope, as, if you did, you would almost certainly see the odd couple of red cells "kissing each other", even if they have been incubated in isotonic saline.

The other thing is (and I speak with some 43 years of working in blood group serology) if the reactions in the tube are THAT weak, the chances of any atypical alloantibody that you might miss being clinically significant are absolutely minute.

If you are still worried, however, get a more experienced worker to read your tests as well, until you feel confident.  That is how I learned when I started.
I wish you the best of luck in your future career.