W.A.R.M. Autoadsorption QC

[ABQ bloodbanker]

Hi guys,

I may be just having a bad day, but I can't seem to figure out the Quality Control procedure on the package insert of Immucor/Gamma's W.A.R.M . Auto Adsorption...

It states that "the activity of WARM may be deemed sufficiently active if it can be shown that treated red cells show enhancement of Rh antigen and denaturation of a Kell system antigen. It is recommended that a reagent red cell of known phenotype be treated with WARM to demonstrate enhancement and denaturation with appropriate antibodies."

So what I am getting from this is to take 2 different cells (screen cells, one K+ and one E+ for instance) and treat them with the WARM solution, along with the patient you are treating, and once done, use Anti-K and Anti-E on those screen cells to see if they are enhanced and denatured???

Does that mean you need to test them before you treat them and record the reactions to see if they changed? Most antisera give a 3 -4+ reaction, so it may be hard to tell if it was enhanced.

I am writing the procedure for this and I need specific instructions in performing the quality control.

Thanks for your Help...

ABQ Bloodbanker

[marilynm]

If you do not have human patient antibodies, and use commercial antisera, I think it is appropriate to use "diluted" antisera labelled "for QC purposes only" and dilute the anti-K and anti-E on day of use and only the amount you need that day. If they are monoclonal, you can probably get a good dilution to give a 2+ reaction on untreated cells and 3-4+ on treated.

Interested in hearing other suggestions.

Marilynm

[asimard]

I think the point of testing is is that depending on what you are using for treatment, one antigen will be destroyed and the other not destroyed. If its a known cell, K +, E - or K - E+ then yes, it would be best to run these cells non-treated at the time of reading the treated cells to prove that pos is pos and neg is neg and expected results are obtained.

[marilynm]

The purpose of the QC is to show that the treatment was successful and the reagent was working properly, so destruction of K antigen for the DTT part of WARM and nondestruction of E antigen. However, for the enzyme (papain) part do you also need to show destruction of an antigen and nondestruction of another?

We use a diluted anti-D to show enhancement with ficin-treated cells vs untreated cells to show that the ficin solution is active and the treatment was successful. We also use an anti-Fya to show destruction. We do not test every cell we treat, we only show that the enzyme is working.

Marilynm

[David Saikin]

I agree with Marilyn . . . I only use WARM to destroy K system ags, so that's all I use; after pretreatment, I run a treated and untreated cell with the antiseum. If I use ficin, I check its functionality using anti-M instead of Fya (less work for me).

[AMcCord]

I've been using a format similar to what Marilyn outlined. For Rh enhancement, I use a dilute anti-D that normally doesn't give me a positive reaction until AHG phase...after treatment of the cell with WARM, I get 1-2+ after 37C incubation. I figure that shows enhancement.

[Eagle Eye]

We use commercially available W.A.R.M. and follow manuf. instruction. We take K+E- cell and K-E+ cell and treat them with WARM along with patient's cell. We run untreated and treated cells against anti-E and Anti-K which shows enhancement of E antigen and Kell antigen gets destroyed.

[Dr. Pepper]

You might consider doing PEG autoadsorptions as outlined in the procedures section of the AABB tech manual. It's a lot cheaper and faster than WARM. There's a caution in the procedure about a potential dilutional effect. We tried the procedure on several spiked samples and saw equal or greater reactivity (titer) in the post-adsorption samples than the pre, using 6 drops of PEG/serum mixture. We like it a lot.

[David Saikin]

I have found that using albumin layering with tubes works great for weak Rh abs. I don't get to use it much, but it really works well. I always show it to my students - archaic, but sometimes those old techniques really perform. I concur with DrP about Peg autoabsorptions - they are excellent.