PEG Adsorption

[goodchild]

I'm terrible at using the internet for anything other than the occasional video game. Does anyone have any references to studies done concerning peg adsorptions? Does anyone here have any personal experiences, pros/cons, tips and tricks? Am I going to miss weak antibodies? Am I going to miss certain antibody specificities, ie Kell, because of the peg? Four drops or six? Why do hotdogs come in packs of 10 and buns come in packs of 8?

We had a patient come in a week ago with a really strong cold and warm auto. Using a peg adsorption I was able to get a negative screen, but since my facility really doesn't do that sort of thing often when the next shift showed up that morning they went ahead and sent samples to the reference lab. ARC agreed with my findings.

I was considering taking some of the patients completed cbc tubes and spiking them with some expired antisera to see how easy it would be to pick up the antibody after the adsorption. I'd be curious to hear some suggestions/tips/tricks for that as well.

[David Saikin]

I use PeG autoabosrption for all my tesing (when indicated). It is fast, reliable, and easy. The procedure is in the technical manual, but I use the one from the original paper in Transfusion (sometime in 1999). Use 4 drops of the peg/plasma eluate (2 drops plasma/2 drops Peg). Have I missed anything? . . . No reactions from patients who were transfused, so I'll say "No".

[Eagle Eye]

David, Do you use 2 drops of adsorbed plasma and add 2 drops of PEG? and take it through AHG phase?

[goodchild]

I think he's referring to using 4 drops of the adsorbed plasma which would be approximately 2 drops peg and 2 drops plasma.

The main reason I posted this in the first place is due to what it says in the tech manual under the procedure itself:

"4. Although many laboratories successfully use the PEG adsorption method, some serologists have reported a weakening or loss of antibody reactivity in some samples when compared with results obtained using a different technique. To accommodate this potential weakening of antibody reactivity, some serologists test 6 drops of the PEG-adsorbed serum."

And David when you say

No reactions from patients who were transfused, so I'll say "No".

You're saying that when you use this method and transfuse patients with the results received you've never had any problems? Just making sure I'm reading that right. Thanks for the response.

Edited July 20, 2010 by goodchild
typo

[tubeshaker]

Hi Goodchild,

Here are some references:

W.J. Judd and L. Dake. PEG adsorption of autoantibodies causes loss of concomitant alloantibody. Immunohematology, vol. 17, number 3, 2001. 82-85.

Cid, et. al. Use of polyethylene glycol for performing autologous adsorptions. Transfusion, vol. 45, May 2005. 694-697.

C.L. Barron and M.B. Brown. The use of polyethylene glycol (PEG) to anhance the adsorption of autoantibodies. Immunohematology, vol. 13, number 4, 1997. 119-122.

R.M. Leger and G. Garratty. Evaluation of methods for detecting alloantibodies underlying warm autoantibodies. Transfusion, vol. 39, January 1999. 11-16.

And an interesting one from 2003:

Chiaroni, et. al. Adsorption of autoantibodies in the presence of LISS to detect alloantibodies underlying warm autoantibodies. Transfusion, vol. 41, January 2001. 651-655.

If there's one you want but don't have access to let me know and I'll try to get you a copy.

Cheers,

J

[David Saikin]

David, Do you use 2 drops of adsorbed plasma and add 2 drops of PEG? and take it through AHG phase?

Goodchild has it right . . . the procedure calls for the use of 4 drops of absorbed specimen which is half peg and half plasma, hence you need to use 4 drops. Granted, there are other methodologies for doing absorption . . . ficin pretreatment is a very good one - also very time consuming. There is no magic methodology for anything in blood banking - there is always give and take.

[butlermom]

David, I think in an earlier post you stated you use the PeG autoadsorption for everything. I notice the procedure states to incubate at 37 degrees. Do you also use it for COLD autoadsorptions? I would think there would be problems incubating anything with PeG at 4 degrees.

[David Saikin]

Not for colds - I just stick the whole blood in the refrigerator for those.

[whbb]

TRANSFUSION:Volume 45, May, 2005

"Use of Polyethylene Glycol for performing autologous adsorptions"

[David Saikin]

The original article is in Transfusion, Volume 39, January, 1999 pp11-16.

[Liz]

Great discussion!

Thanks to all for this thread!

Liz

[marilynm]

From an "old timer", the original reference to PEG for autoadsorption was a Letter to the editor of Transfusion 1995;35:713 by Yew Wah Liew entitled Polyethylene glycol in autoadsorption of serum for detection of alloantibodies.

The first reference for weak alloantibodies being not detected using this technique, and a reply by Yew Wah was another Letter to the Editor in Transfusion 1996;36:384 by Kayla Champagne and Marilyn K. Moulds.

It seems it took some years before anyone listened to Kayla and myself about the missing of weak antibodies by this technique and published their own data.

Were these antibodies clinically significant? Ours was an anti-K.

A little trivia for the day. marilynm

[marilynm]

PS: I forgot to mention that the title of the 1996 Letter to the Editor was Autoadsorptions for the detection of alloantibodies-should polyethylene glycol be used?

marilynm

[marquij@caribe.net]

No ficin treatment of the adsorbing cells prior to adsorption at 4C? This will enhance the adsorption process and less adsorptions will be needed.

[marquij@caribe.net]

We perform PeG autologous adsorptions at 37C for 15 mins adding equal amounts of plasma/PeG/adsorbing cells. For testing 4 drops of adsorbed plasma. Works well and if suspicious of underlying alloantibodies, may test with 6 drops to avoid missing any weak reactivity. The problem with PeG according to the literature is that it precipitates proteins and since antibodies are globulins thay may precipitate and be missed.

[rravkin@aol.com]

I think he's referring to using 4 drops of the adsorbed plasma which would be approximately 2 drops peg and 2 drops plasma.

The main reason I posted this in the first place is due to what it says in the tech manual under the procedure itself:

"4. Although many laboratories successfully use the PEG adsorption method, some serologists have reported a weakening or loss of antibody reactivity in some samples when compared with results obtained using a different technique. To accommodate this potential weakening of antibody reactivity, some serologists test 6 drops of the PEG-adsorbed serum."

And David when you say

You're saying that when you use this method and transfuse patients with the results received you've never had any problems? Just making sure I'm reading that right. Thanks for the response.

I have to say that I have never heard of using PEG to differentially adsord Antibodies and I am not sure that it has this capablity outside of varying the incubation time of the reaction volume, so I not surprised with "#4."

[rravkin@aol.com]

I have to say that I have never heard of using PEG to differentially adsord Antibodies and I am not sure that it has this capablity outside of varying the incubation time of the reaction volume, so I not surprised with "#4."

I should add that after reading over several other posts and reveiwing Malcolm's post from "Absorbance/ Adsorbance " thread I see how it is done very clearly. I'll try to read before I write in the future.

[mjshepherd]

The PEG autoadsorption is a great tool, it's simple, inexpensive, and not too time consuming. For our small lab we have a large volume of oncology patients, this procedure allows us to complete testing without sending specimens to reference labs incurring extra time and cost.

[Losmeister]

question-

RE: Elution to attempt to see whether an auto-Ab has specificity

Is it acceptable to do a PEG autoadsorption, THEN Elute?

[Malcolm Needs ☆]

question-

RE: Elution to attempt to see whether an auto-Ab has specificity

Is it acceptable to do a PEG autoadsorption, THEN Elute?

I would say it is acceptable, but the problem is that most auto-antibodies will give a pan-reactive eluate. This is because most of these antibodies have a specificity that is either Rh17 or Rh18, and this means that you have to have -D-/-D- red cells and Rhnull cells available in abundance to prove the specificity once you have eluted the antibody.

What one has to remember is that the antiboy that is free in the plasma may well demonstrate a "common specificity", such as anti-e, but this specificity is misleading and mimicking, rather than a true specificity, and that most of the antibody will be bound to the red cells, and when it is eluted, it shows its true specificity of, usually, anti-Rh17 or anti-Rh18.

In almost all cases, therefore, it is not worthwhile doing it.

Sorry; nice idea, but............

:o:o:o:o