Hi All,

I am wondering, how exactly are Warm autoadsorptions performed with PEG? I have always performed them with W.A.R.M reagent, but I have heard that using PEG is more cost effective and yields better results. Also, what exactly IS the difference in cost?? If someone could please explain this to me, it would be so incredibly helpful!!

There is a procedure in the technical manual I believe.  Basically it is equal volumes of cells, plasma and peg.  Incubate for 15 minutes, centrifuge and remove supernatant (save the cells 'cuz you can reuse them if you need to repeat the absorption), test the supernatant using 4 drops (2d peg/2d plasma).  I use it for all my warm autos - it works excellently.  I do this testing in tubes - I can never absorb out all the autoab if I test in gel.

 

In another post somewhere on this site someone discussed the fact that if the absorption showed no allosensitization they just used the immediate spin xm and did not have to worry about any interference from the autoab (might have been jpcroke).

 

Cost:  I can't go there.  Warm is a bit expensive.  I only use it to destroy Kell system ags and use it well past its outdate (it still works and so the the controls I run).

Edited September 9, 20159 yr by David Saikin

Thank you for your input on this method! I am wondering though, tube testing is less sensitive than gel, so are you truly clearing it when you are using this method?? Also, I don't understand why you cannot answer about the cost difference. Why?

Well, for one: reagent costs are usually on contracts and the terms of the contracts generally include not sharing details about prices.

Goodchild is correct about pricing - but WARM is more expensive than PeG.  I used to have a WARM protocol for absorptions - very complicated, esp when compared to Peg.  I use tubes because I can never absorb all the autoab out of a specimen if I use gel to test it with.  I don't need that increased sensitivity to r/o alloabs.  I have found that if I get a 4+ anti-IgG ab screen in gel, when I do it in tubes it is usually 1-2+.  This usually only takes one absorption to remove.  Most of the time there is no reactivity of the autoab left; rarely I have had to do 2 absorptions (and once I couldn't remove it with 4 but the tertiary care hospital couldn't either so . . .).    One must also remember that tube testing is still the standard (I think).  PeG absorptions sure beat the method of using enzyme pretreatment with the following incubations and absorptions.  It is quick and very reliable. 

 

Hope this helps.

I guess I am just confused about why pricing is such a secret. I get that it depends on contract, but I am asking in order to get a general price range. I am the Lead Blood Bank Tech at my facility, and We don't currently perform warm autoadsorptions. It seems like lately, we have been getting quite an increased number of patients with a warm auto antibody. I would like to get an idea of the cost of performing adsorptions, so that I can present this info to my supervisor.

I would like to get an idea of the cost of performing adsorptions, so that I can present this info to my supervisor.

 

It's easy enough to get an idea of this from the companies themselves - they can give you more of an idea on discounts available based on order size.

I guess I am just confused about why pricing is such a secret. I get that it depends on contract, but I am asking in order to get a general price range. I am the Lead Blood Bank Tech at my facility, and We don't currently perform warm autoadsorptions. It seems like lately, we have been getting quite an increased number of patients with a warm auto antibody. I would like to get an idea of the cost of performing adsorptions, so that I can present this info to my supervisor.

 

At my pricing levels WARM is more than twice the cost of PeG (10 btls each).  When you reconstitute WARM it has a finite life span.  I usually use only 1-2 mL of PeG for an absorption and I can still use the btl until it outdates. 

Ditto ditto ditto! Half the time, half the price, half the work. Doesn't smell like skunk juice. What's not to like?

 

Don't worry about a loss of sensitivity - you're still testing in PeG at the end of the day. As Malcolm has pointed out, we weren't killing patients right and left in the half century before gel. Tube be or not tube be.......

. Tube be or not tube be.......

I did a talk in Portland (more than) a few years ago - that was the title.

David,

 

You say to save your adsorbing cells to use for a 2nd adsorption if necessary.  Do you enzyme treat them initially?  Do you do anything to them before putting the serum back on the 2nd time?

 

Thank you

I don't enzyme pretreat. You can just pour the supernatant from the initial absorption back on then 37C for another 15 min.

I've been thinking about enzyme pretreatment but I don't think so (maybe in a rare case . . . don't ask me what)

Do you typically achieve success with just 1 absorption, or do you routinely do more than 1?  Also, do you add PeG?

Do you typically achieve success with just 1 absorption, or do you routinely do more than 1?  Also, do you add PeG?

Using the PeG autoabsorption - usually one does the trick BUT I am testing in tubes (see above comments)

I can't find the PEG adsorption SOP in the Technical Manual.  Does anyone have an electronic version to share?

Mabel

do you have the latest TM? It would be on the electronic file on the inside back cover.

Mabel

do you have the latest TM? It would be on the electronic file on the inside back cover.

Mabel, I'd be happy to send one if you need one. (And that credit card-sized flash drive is so cool...)

Edited October 22, 20159 yr by Dr. Pepper