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Testing enzyme treated panel cells with buffered gel card


Clarest
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Hi all,

Below is what it says in the Instructions for Use (IFU) of MTS Anti-IgG Card.

"The use of enzyme-treated red blood cells with the MTS™ Anti-IgG Card may detect clinically insignificant antibodies. The MTS™ Buffered Gel Card is recommended when using enzyme treated cells."

I am confused :huh: If a buffered gel card is used, does that mean it is NOT an indirect antiglobulin test as I don't see where the AHG reagent is added. On the other hand, in the IFU of MTS Buffered Gel Card, it has the following statement.

"This MTS™ Buffered Gel Card can be used in ABO Serum Grouping as well as direct agglutination i.e., cold and warm antibody detection."

I would assume the warm antibody mentioned here is not necessary to be an IgG antibody?! 

Then, how would we use the enzyme panel to identify the clinically significant IgG antibody with MTS gel method?

Thank you for your input!

 

 

 

 

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NHSBT routinely perform IAT and enzyme IAT using BioRad LISS/Coombs cards. (Anti-IgG + C3d). I found this helps identification with some weak antibodies or where there is a mixture and one is enzyme sensitive.

At my current hospital we still perform enzyme panels on NaCl cards. There are less reactions with antibodies we don't wish to detect.

Of course you can't use enzyme techniques alone when identifying antibodies so it's a choice between; improved identification and detecting more insignificant antibodies (enz IAT) or Detection of fewer bothersome  antibodies but harder to ID some cases (enzyme).

Maybe use IAT and enzyme routinely and employ enzyme IAT to help solve tricky/weak examples?

You would have to do some kind of testing/documentation/risk assessment etc. if you're not following manufacturer's package insert I assume.

 

 

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2 hours ago, RichU said:

NHSBT routinely perform IAT and enzyme IAT using BioRad LISS/Coombs cards. (Anti-IgG + C3d).

This statement is completely true, BUT the fact that NHSBT RCI Laboratories started to use these routine techniques followed a huge amount of work performed by Gordon Burgess when he was the Reference Service Manager at NHSBT-Cambridge Centre (before he became Head of RCI in NHSBT) to show that these were viable techniques that passed prolonged Quality Assessment.  To introduce such techniques without such work would not have allowed RCI to pass inspections by our various assessors.

I doubt if Clarest would be able to introduce such techniques into Canadian laboratories without similar work.

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11 hours ago, Clarest said:

Hi all,

Below is what it says in the Instructions for Use (IFU) of MTS Anti-IgG Card.

"The use of enzyme-treated red blood cells with the MTS™ Anti-IgG Card may detect clinically insignificant antibodies. The MTS™ Buffered Gel Card is recommended when using enzyme treated cells."

I am confused :huh: If a buffered gel card is used, does that mean it is NOT an indirect antiglobulin test as I don't see where the AHG reagent is added. On the other hand, in the IFU of MTS Buffered Gel Card, it has the following statement.

"This MTS™ Buffered Gel Card can be used in ABO Serum Grouping as well as direct agglutination i.e., cold and warm antibody detection."

I would assume the warm antibody mentioned here is not necessary to be an IgG antibody?! 

Then, how would we use the enzyme panel to identify the clinically significant IgG antibody with MTS gel method?

Thank you for your input!

 

 

 

 

Hi @Clarest,

The IgG is already in the card. It is that tiny amount of clear liquid at the top of the card. Rest assured, it is an AHG test. 

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Hi Clarest,

I am not familiar with the MTS product line, but to me it says that enzyme treated cells can be used in AHG card (the human anti-IgG is already in the gel card of course) though you may experience some non specific reactions plus a higher detection rate of unclinically significant antibodies (specific but unwanted...). This uses (enzyme + AHG), as mentionned above, should be well understood/assessed/validated/targeted => you will as well enhance the reactivities for other clinically significant antibodies such as anti-Jka which is the purpose. Then, they rather recommend to use these enzyme treated cells in their "neutral-saline" cards (called buffered gel), which does not contain AHG. It is propably a way to prevent you to complain if you get an increase of positive reactions to be further investigated whereas this is mostly due to unclinically significant antibodies. Enzyme reactive antibodies (e.g. anti-Rh) are "expected" (why antibodies do no read IH books...) to agglutinate in neutral-saline cards as ABO agglutinins do, without AHG. Having said that, anti-Jka are better detected in coombs + enzyme ....    

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Wanted to say... anti-human IgG of course and not human anti-IgG..... sorry for that. 

I use the opportunity to add that AHG card should have a slightly green colored gel (based on similar products available in Europe) whereas the neutral-saline should be transparent.

 

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