Least Incompatible units

[jojo808]

Our lab does not work up warm autoantibodies, we send them out to a reference lab for consultation. My question is: If a warm auto is identified (with or without underlying alloantibodies), do we need a medical director/pathologist approval for transfusing "least incompatible" units? We do have the ordering physician sign a document to allow the transfusion of these units.

[David Saikin]

If you have a "Least Incompatible" form you must have a policy that allows its use, therefore I would assume that this is approved by your Medical Director. I would let you MD know prior to release just so they can interact with the pt's MD if they think it necessary.

(Least incompatible is like saying someone is a little pregnant).

If your pt has a WAIHA any transfused blood will be treated just like the pt's own. The risk of underlying alloabs cannot be taken lightly. I give these pts Rh phenotype specific rbcs as I have found that when I did not do so they made ab to the Rh ags which they did not possess (scary).

[tbostock]

I agree with David.  I dropped the term "least incompatible" a long time ago.  It gives the physician a false sense of security.  They have done studies that a 1+ incompatible unit will do a patient no more or less harm than a 2+ incompatible unit.  In vitro grading/results do not correlate what will or will not cause harm in the patient.

 

I know of some labs that use the term "serologically incompatible" when it's just the warm auto activity and all underlying alloantibodies were ruled out.  This is more realistic than "least incompatible".

 

At my place we just call them all incompatible and have the MD sign a release, whether or not the allos have been ruled out.  We like putting a healthy fear out there so they watch the patient more closely.

Edited May 6, 2014 by tbostock

[jojo808]

Thank you for the response. Yes I agree the terminology is confusing but technically the units will be incompatible due to the positive reactions from the autoantibody. I like "serologically incompatible" (makes sense). And yes we do have a policy that is approved by our medical director but we did not notify him of each case. But I think we will definitely implement that ... doesn't hurt to keep our MD informed. Thanks again!

[Alana]

We report these units as incompatible. We prescreen the units for compatiblity in the method the underlying allos were ruled out in and xm in the method that has reactivity. We like to give the units that are not any more reactive then the warm auto (compare with the auto control) but this may be totally acedemic and making us feel good.

 The pathologist is notified with the goal of having conversion with the MD about the patient, the need for transfusion, the risk and benefits of this treatment, and other treatments that may help like IV iron or EPO.

[Malcolm Needs ☆]

A paper/editorial that I have quoted many times before:

Petz LD. "Least incompatible" units for transfusion in autoimmune haemolytic anemia: should we eliminate this meaningless term? A commentary for clinicians and transfusion medicine professionals. Transfusion 2003; 43 (11): 1503-1507.

[mcgouc]

Before we went on our current computer system we used "incompatible". Unfortunately, our computer won't let us put the unit in a crossmatched status so we can issue it if we interpret as incompatible. So, we moved backwards & now interpret it as "least incompatible" so we can issue (with an override).

[jojo808]

All comments are very informative ... I'm a newbie to the site but am enjoying all the responses! It's so great to collaborate with people from other states and finding out that we are all pretty much on the same page and playing for the same team which is our patients' safety and well being.

 

I've been in this field for a little over 20 years and started out loving the job but the times have shown me the "ugly business" side of the job and frankly it is not as enjoyable as it was. You guys have made it interesting again, sounds cliché' but it's true. I'm sure I'll have more questions later but thanks again for validating what we do!

[Joanne P. Scannell]

We, too, have dropped using the term 'least incompatible' way back when (along with 'in vivo crossmatch', I think) ... been so long, I forgot ... 1970's, 1980's?

 

1. Not all antibodies cause RBC destruction.

2. Not all antibodies that do, cause them in the same way.

3. Grade of reactivity is dependent upon the method and for some platforms, upon the tech performing the test.

4. Grade of reactivity is not proportional to the effectiveness of destruction.

 

I think the only way to determine variations of compatibility is by using monolayer methods = specialized testing.

 

Going back to 'the letter of the law': If the patient has no clinically significant allo antibodies, there is no requirement to perform an extended crossmatch. 

 

So, once this is established either by alternate testing methods (gel is very good at picking up autoantibodies) or differential absorptions, the Immediate Spin crossmatch is all that is required.  Thus, eliminating the need for conversations about 'least incompatible'.

 

If 'no clinically significant antibodies' cannot be established, it is prudent to issue antigen-negative matched RBCs to avoid the possibilities.  Some hospitals do this regardless of the current antibody status just to avoid future antibody production.

 

Of course, if there are underlying antibodies, then an extended crossmatch is required.  This should be performed with the method that was used to circumvent the auto-antibody.  Example: Assume patient has positive DAT.

Gel: All cells positive

Albumin (or LISS or PEG or whatever): Anti-E.

Use Albumin (or LISS or PEG or whatever) to perform extended crossmatch.  If this is negative and the unit is E-neg = compatible RBCs.

 

And yes, this is what we do.

[rravkin@aol.com]

JPCroke, very interesting post here; can you further explain the specifics of the "monolayer methods, specialized testing?" Also, in the example you give with the Anti-E, are you not first antigen typing these units, or are you just performing the extended crossmatch (Coombs Crossmatch) and assuming with compatibility the units are negative for Anti-E?

[Malcolm Needs ☆]

We, too, have dropped using the term 'least incompatible' way back when (along with 'in vivo crossmatch', I think) ... been so long, I forgot ... 1970's, 1980's?

 

1. Not all antibodies cause RBC destruction.

2. Not all antibodies that do, cause them in the same way.

3. Grade of reactivity is dependent upon the method and for some platforms, upon the tech performing the test.

4. Grade of reactivity is not proportional to the effectiveness of destruction.

 

I think the only way to determine variations of compatibility is by using monolayer methods = specialized testing.

 

Going back to 'the letter of the law': If the patient has no clinically significant allo antibodies, there is no requirement to perform an extended crossmatch. 

 

So, once this is established either by alternate testing methods (gel is very good at picking up autoantibodies) or differential absorptions, the Immediate Spin crossmatch is all that is required.  Thus, eliminating the need for conversations about 'least incompatible'.

 

If 'no clinically significant antibodies' cannot be established, it is prudent to issue antigen-negative matched RBCs to avoid the possibilities.  Some hospitals do this regardless of the current antibody status just to avoid future antibody production.

 

Of course, if there are underlying antibodies, then an extended crossmatch is required.  This should be performed with the method that was used to circumvent the auto-antibody.  Example: Assume patient has positive DAT.

Gel: All cells positive

Albumin (or LISS or PEG or whatever): Anti-E.

Use Albumin (or LISS or PEG or whatever) to perform extended crossmatch.  If this is negative and the unit is E-neg = compatible RBCs.

And yes, this is what we do.

Brilliant post.

The ONLY thing I would say is that monolayer methods, along with the chemiluminescence test, have proved to be less useful than was first thought. For example, anti-Inb gives a positive result, because it can cause a haemolytic transfusion reaction, but also gives a positive result vis-à-vis HDFN, which it does not cause. Some other antibodies also give "false positive" results by these methods.

That having been said, I repeat, a brilliant post!

[lawblood]

Well, this discussion has given this old-fashioned Blood Banker something to think about.

Interestingly, our donor center reference lab has stopped automatically supplying phenotypically-matched RBCs if there are no alloantibodies detected under the WARM.

If the patient later develops an allo, then pheno-matched RBCs are provided.

 

We had a slightly different situation occur in our lab last week.
Patient had a history of WARM due to Evans Syndrome (autoimmune).  This time however, only the DAT was positive.  The Gel screen and IgG crossmatch were negative.

The eluate was reactive with all cells. The sample was sent to the reference lab and they came back with the same results.   They only recommended what we had already done. 

My question is:  if the WARM is not spilling over to the plasma, would it be safe to issue crossmatch (in our case, Gel)-compatible RBCs for transfusion?  I think I am getting too conservative in my old age. 

[Malcolm Needs ☆]

In brief lawblood, and from my point of view, yes!

[David Saikin]

 

In brief lawblood, and from my point of view, yes!

 

I definitely agree with Malcolm. No reason not to.

Edited May 12, 2014 by David Saikin

[Joanne P. Scannell]

Ditto!

[Joanne P. Scannell]

JPCroke, very interesting post here; can you further explain the specifics of the "monolayer methods, specialized testing?" Also, in the example you give with the Anti-E, are you not first antigen typing these units, or are you just performing the extended crossmatch (Coombs Crossmatch) and assuming with compatibility the units are negative for Anti-E?

See an earlier post here about the monolayer method ... guess that doesn't pan out the way they thought it would.  And I don't know of any 'routine' Blood Bank that runs their testing using this method.

 

In my example, since gel picks up 'everything' while the lesser sensitive method does not, we use the lesser sensitive method to perform the crossmatch.  And yes, we would transfuse antigen-negative, crossmatch compatible RBCs (crossmatch compatible with Albumin).

 

BTW: In Sunquest, we add the testing we do.  XMTS for the extended crossmatch with gel (1+, Incompatible) and XALB for the extended crossmatch with 22% Albumin (0, Compatible).  Since the patient has an Anti-E, the system requires the unit be typed/recorded as 'E-neg.'  The 'test' %TS (Transfusion Status, part of the crossmatch battery) is the determining result - the techs final interpretation.  In this case, we answer it 'OK to Transfuse' because we have determined that it is.  If we answer 'Not OK to Transfuse', the system would release the unit from the patient, i.e. no unit tag, no issuing it to the floors.

 

Of note, in the days before gel/solid phase, we probably wouldn't have seen half of these warm autos.

 

Also, a related case of interest ... for your further amusement ...

We had a 19yo female present in Sickle Cell crisis last week.  She has a positive DAT (IgG only), an Auto-Anti-E (2-3+ gel and Albumin), a 'Warm Autoantibody of Undetermined Specificity' (1+gel only) aaaand is producing Anti-e (along with a history of Anti-N).  Somewhere along the way in her short life, she got transfused with E-neg/e-pos RBCs (not all hospitals give antigen-neg RBCs proactively OR someone was thinking they should avoid the E antigen because it has a name).  This is a prime example of why we should NOT honor Auto-'identified' antibodies because of the super exposure to the 'other' antigen.  Now, this young lady will be dealing with an Anti-e the rest of her life ... through multiple transfusions (due to her Dx) and through pregnancies with an Rh-antibody.  A disservice and a shame.

[Michaele]

When we have to give incompatible due to a warm auto, we have the medical director sign a deviation form on the patient and we keep the deviation form in a noticable spot until the specimen expires. 

[David Saikin]

  

per JPCroke

"In my example, since gel picks up 'everything' while the lesser sensitive method does not, we use the lesser sensitive method to perform the crossmatch.  And yes, we would transfuse antigen-negative, crossmatch compatible RBCs (crossmatch compatible with Albumin)."

I agree - I can never absorb all the autoab and test with gel. I usually use a PeG autoabsorption and can then do my xm's/absc/abid/whatever. I have never used "just" albumin in lieu of absorptions - I may have to play with this concept. Thanks!

[Dansket]

If you have a specific form that requires a physician's signature prior to transfusion of "crossmatch-incompatible" or "least-incompatible" red cells, would you post it please.  I have to develop such a form and appreciate any assistance.  Thanks

[AMcCord]

Here's my new form, plagarized from  inspired by many sources.

Request for Release of Blood and Blood Products.doc

Edited September 15, 2015 by AMcCord