No enhancement

[jojo808]

What do you think about using tube method with no enhancement for Warm autoantibodies??

It states in the technical manual that "antibody detection methods using PEG, Enzymes, Column agglutination, or solid phase red cell adherence generally enhance autoantibodies".

"While methods using LISS or Saline tube methods may not detect autoantibodies, but most significant alloantibodies will be detected".

I'm asking because we send our workups to a reference lab. However we had a patient with a history of a warm auto, nothing underlying, came in with 2+ reactions (Gel) on both screen cells. Autocontrol was positive 1+ and DAT was negative. We did a panel using tube method, 3 drops serum to 1 drop cells incubated for 1 hour with negative results.

Would this procedure be okay? Would it be safe to say there is nothing underlying the Warm auto?? Why would you have to use adsorbed plasma for testing (especially if the DAT is negative). 

[Malcolm Needs ☆]

We use the LISS tube IAT daily in my Reference Laboratory, and, in the right hands (i.e. those who are trained to competency, and are able to demonstrate continued competency, in the technique - which, before the advent of PEG, CAT and solid phase, used to be everyone!), it is perfectly safe.  As I have said before on this site, at one stage that was all we had, and the cemeteries were not full of people who had died of transfusion reactions!

In most cases, not all by any means, but in most cases, although the avidity of the auto-antibody is strong, the titre is not that high, whereas most, not all by any means, alloantibodies that are clinically significant, have a higher titre, even if their avidity is not much to write home about.

The technique is even more useful in cases of a cold AIHA, where the cold auto-antibody tends to have a wide thermal amplitude, but rarely can be detected by tube IAT at 37^oC, but, of course, clinically significant alloantibodies will be reactive at 37^oC.

Of course, in one way, this technique is safer than using alloadsorbed plasma.  There is no way that alloadsorption red cells would be negative for even one high prevalence antigen (such as Vel, Jr^a, At^a, etc), let alone negative for multiple high prevalence antigens, and so, if the patient happens to have an antibody directed against a high prevalence antigen underlying the auto-antibody, then the antibody directed against the high prevalence antigen will be adsorbed out, just as the auto-antibody will be adsorbed out, and, hey presto, you have a compatible cross-match, and a patient with (hopefully no more than) a delayed haemolytic transfusion reaction.

[John Eggington]

The 'DAT neg', 'auto pos', gal auto antibodies are almost always best managed by using a tube technique. The autoantibody may well bind during the tube incubation phase but is eluted away during the wash phase. You usually find that if you do a gel DAT, but add patient plasma to it and incubate like an IAT, the  cells will be IgG coated.

[jojo808]

Thank you so much, I am relieved to hear that!! I was initially taught with tube method, with and without enhancement (in the early 90's) and since then, thought that the newer potentiating reagents were somewhat 'superior' to the others. As I have read into more forums I see that they are just different. It's has been made more clear to me!

Spoiler

 

 

[OxyApos]

We have solid phase and occasionally get these "warm auto" like reactions.  Doing a tube screen w/o enhancement ( aka 30" saline) is our problem solving method.  If the patient has been transfused we'll do AHG XM just to make sure.  Like Malcolm says, before all these new fangled but convenient techniques people were not dropping dead from every transfusion.

 

[jojo808]

Would you use Polyspecific AHG or Anti-IgG (mono-specific) for this method?

[Malcolm Needs ☆]

Personally, I prefer to use monospecific anti-IgG, for the simple reason that, if there are any "cold auto-antibodies" floating around, there is the possibility that the red cells will be coated with anti-C3d, and I don't want to detect this.

[jojo808]

Thank you 

[COTTONBALL]

I have to say, all of the questions and answers here are great.  I get calls from my techs who are very fearful of those least incompatible/compatible reactions on crossmatch, even after our reference buddies have detected no underlying alloantibodies. 

I appreciate Malcolm's care in saying "in the right hands".  Competency and proper training is everything.  I fell in love with antibodies/antigens/panels/elution/adsorptions.. 26 years ago as a student.  However, today I (hospital TS) trust and rely heavily on the expertise of our reference family.  Have even delivered chocolates to them once a year.  Thanks for all that you do.

[Malcolm Needs ☆]

2 hours ago, COTTONBALL said:

However, today I (hospital TS) trust and rely heavily on the expertise of our reference family.  Have even delivered chocolates to them once a year.  Thanks for all that you do.

I trust that ALL of the people in charge of the transfusion laboratories in the 50 odd hospitals on our patch at Tooting read your post COTTONBALL, and take good head of the bit I have quoted!!!!!!!!!!!!!!!!!!!

[galvania]

Would count as corruption Malcolm!

[Malcolm Needs ☆]

2 hours ago, galvania said:

Would count as corruption Malcolm!

I'd eat the evidence Anna!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Liz0316]

We use a saline method where by we use 4 drops of plasma to one drop cells, to super-saturate the cell. Incubate 30- 60 min and use IgG at coombs.

This method has served us well in patients with warm autos. Malcom, of course, went into detail about strong bonds and titers, etc., but I tell my techs that "any self respecting allo- antibody will be detected by this method" -

and yes, I'm old school. So it was, back then, once you have discovered there is a problem, or you have actually detected an antibody, going back  to a saline method is a fine and accepted way to get around the garbage you may be detecting in GEL or other "enhancing" method.

Liz