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column agglutination (gel card) technique for crossmatching


drwajiha

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dear friends,

Hi, I am interested to get views from the senior people about using complete cross match cards by BioRad (Diamed). Can these replace the saline phase and albumin phase of serological cross match completely? Can any one post their policy and procedures using these cards or similar methodology cards to give information how to use these cards effectively.

Thank you

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dear friends,

Hi, I am interested to get views from the senior people about using complete cross match cards by BioRad (Diamed). Can these replace the saline phase and albumin phase of serological cross match completely? Can any one post their policy and procedures using these cards or similar methodology cards to give information how to use these cards effectively.

Thank you

Unless we have to use a tube technique (because of free auto-antibodies in the plasma), almost every cross-match performed by NHSBT in England and, I think, most serological cross-matches performed by hospitals in England, are performed by column agglutination technology, and have been for some years.

Unfortunately, I am now on annual leave until 21.08.12, and so am not in a position to post our standard operating procedure for this until I get back to work, but I will try to remember to do it then.

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We use Immediate Spin crossmatching or Electronic Crossmatching for qualified recipients. For those who require an AHG crossmatch, our primary method is the Ortho IgG gel card. However in January of 2011, we received a disclaimer from Ortho stating that these gel cards do not contain FDA approved labeling for the detection of IgM antibodies and are not adequate to demonstrate ABO incompatibility. I don't know if this applies to the Diamed complete crossmatch cards since I am not familiar with this product. I would definitely consult the manufacturer's instructions in this case. Our P&P rely on the validated computer system to detect ABO incompatibilities. As for replacing the saline and albumin phases, I believe the gel method is sufficient for use when a patient has demonstrated a significant antibody.

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Can these replace the saline phase and albumin phase of serological cross match completely?

The albumin phase of crossmatching is completely obsolete. This dates from the days when Coombs reagents were much less reliable. What you need to do is firstly an antibody screen to make sure there are no atypical antibodies present. Then if you want to do a crossmatch all you need to do is select ABO/D identical or compatible blood (and depending on the case, maybe Rh phenotype and K as well) and then just match the donor cells against patient plasma in a LISS/Coombs or Coombs IgG card. If you need to check the donor ABO group from a blood bag that has already been typed in a transfusion centre then you can do that with an ABD card. If you write me a private message I can advise you in more detail

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GEL METHOD

The gel test was developed in Switzerland in the late 1980s as a way to standardize the method of obtaining agglutination and to provide a simple and reliable way to read it. (Lapierre Y, Rigal D, Adam J, et al. The gel test: a new way to detect red cell antigen-antibody reactions. Transfusion 1990;30:109-13 ) Besides these benefits, the test also provided a way to do antiglobulin tests without having to wash them. Also, the test uses small volumes of serum and cells and is capable of using automated reading.

That is NOT everything,the Gel method is better than conventional tube method because of its Sensitivity,Simplicity and Stability of results,thus permitting reading and verification later on,its a rapid and innovative method for detection of antigen antibody hemagglutination reaction.

The Gel card method testing takes 20-25 minutes as compared to 90 minutes by the conventional tube method.

Gel Principle/Method

Unlike in tube tests, in the gel method agglutination does not take place in a liquid phase but rather in a gel contained in a special microtube. Briefly, the method is this: patient plasma and a 0.8% suspension of red cells (e.g., screen cells) in a low ionic medium (LIM) are dispensed into the microtube and incubated at 37∞C for 15 mins; the card containing the microtubes is then centrifuged at a controlled speed for 10 minutes. At the start of centrifugation the cells are separated from the serum; then they meet the antiglobulin serum contained in the microtube; finally the cells are trapped by the gel (if agglutinated) or pellet to the bottom of the tube.

THE PROCEDURE:

A 0.8 % suspension of the donor’s red cells was prepared by mixing 10 μl of red cells in one ml of LISS (ID diluents). 50 μl of the donor’s red cell suspension

is added to the microtube, followed by 25 μl of the patient’s serum.

The card is incubated at 37°C for 15 minutes, then centrifuged in ID centrifuge and results read.

No agglutination indicates that the donor’s blood

is compatible with the recipient and suitable for transfusion.

A negative reaction displays pellets of RBCs at the bottom

of micro tube with no aggregates in gel matrix. The presence of agglutination is indicative of incompatibility.

Positive results are graded for 1+ to 4+. A 4+ reaction isindicated by a solid band of red blood cells (RBCs) on top of the gel. A 3+ reaction displays agglutinated RBCs in the upper half of gel column.

A 2+ reaction is characterized by RBC agglutinates dispersed throughout the column,while a 1+ reaction shows RBC aggregates in mainly lower half of the column.

I hope this will help.:D

Edited by Abdulhameed Al-Attas
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Mabel - the American 'Ortho' gel is pretty much the same as the 'DiaMed' (now BioRad) gel (Ortho in Europe is not gel but still CAT). And in Europe the trend has been moving steadily away from immediate spin for ABO antibodies for many years. I would say, in general, tubes are still more sensitive that any form of CAT for weak ABO antibodies IF they are used correctly

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