Does anyone have a category for HLA antibodies as a reportable antibody?  We just have non-specific (which I hate) and unable to identify right now, but I have had several I felt were HLA, based on the fact that Ortho puts HLA designation on some of their cells.  Do you think it is a responsible act to call them HLA without using a reference lab to verify?  Or does it really matter?

 

Thanks!

We Literally just had this happen to us.

Patient was only reacting with HLA+ cells on the Screening Cells and with Panel A and Panel B.  We did call the reference lab and they verbally verify it. 

We don't even have a non-specific or unidentified  option right now. ( One more thing to add to my list)

So, I'll be curious to know how you guys  are doing it as well.

Sending a sample to a Reference Laboratory can be expensive in the USA (as I understand it, anyway).

Buying a small amount of chloroquine diphosphate (CDP), which is used to remove HLA antigens from red cells is relatively cheap, and so you could test your plasma with red cells treated with CDP "in house" and get your own results.

From the manufacturer's insert:  "The results obtained in this application should be interpreted with particular caution, as there is clear evidence that the reactivity of red blood cell surface antigens may be impaired by chloroquine treatment, which could lead to a negative reaction with a weakly reactive antibody other than one of "anti-Bg" specificity."

Paraphrasing Issitt and Anstee (Applied Blood Group Serology, 4th Ed), Bg antigens can appear, or disappear over time.  So a donor who had previously typed Bg- by a manufacturer, may later have the antigen, but appear on the panel as Bg- (or HLA- as they do now).  The opposite may very well happen too: a cell marked Bg+ may very well be Bg- in the future.

My only advice is, if you decide to use this reagent, you must be sure that you have performed an adequate rule-out of all other antibody possibilities as required by the FDA.  With the exception of the K antigen (as not all panels have K+k- cells), I'd make sure that I had homozygous crossouts for all of the other required antigens prior to resorting to chloroquine diphosphate treatment.

I'm not disagreeing with Malcolm, only cautioning that there is an appropriate time to utilize chloroquine.

I totally agree with your statement StevenB.

9 minutes ago, StevenB said:

From the manufacturer's insert:  "The results obtained in this application should be interpreted with particular caution, as there is clear evidence that the reactivity of red blood cell surface antigens may be impaired by chloroquine treatment, which could lead to a negative reaction with a weakly reactive antibody other than one of "anti-Bg" specificity."

 

Answering the original question, I don't believe you need to send every suspected anti-Bg antibody to a reference laboratory for confirmation (even though we'd like the business!).  Just be cautious; make sure you have appropriate crossouts as I mentioned above.

I definitely wouldn't assume a reaction was due to an HLA antibody if I had not ruled out other significant antibodies.

We have an interpretation of "anti-Bg"

So is anti-Bg more politically correct than anti-HLA?  I still might turn them out as unidentified, possible HLA antibody.

Well, both are somewhat non-committal, as there are three Bg specificities (Bg^a, Bg^b and Bg^c), and these have, in order HLA-B7, HLA-B17 and HLA- A2/A28 specificities, and so I would think, unless the exact specificity is known, either anti-Bg or anti-HLA should be acceptable.

I am investigating the CDP method today. Technical Manual has the procedure, 17th edtion method 2-20 is what I am looking at. In the notes, #6 it states "in addition to its use for removal of autoantibodies, this method can be used for removal of Bg (HLA) related antigens from red cells. Appropriate Bg controls should be used." What is the appropriate Bg controls???

 

Does anyone have an opinion on Immucor's Gamma-Quin CDP solution?

I have used Immucor's Gamma-Quin and it has worked well for what I used it for - for example: it made quick work of ID'ing antibodies under an anti-k in a survey a while back. I haven't really played with it for Bg antibodies, but I suspect it would do the job.

If we get a stray reaction with, say, a Bga positive cell that doesn't seem to be due to anything else, we will try to find another cell or two listed by the manufacturer as Bga-positive, and if they react report the antibody as anti-Bga as we would with any other antibody identified. We also have a "probable HLA antibody" as a reportable choice. In which case we would look for one or two stray reactions, usually weak, that again don't add up to anything else, eliminate all other choices by standard techniques, no significant difference in reactivity with LISS and PeG, doesn't prewarm away, and hopefully a good titer (although they don't have to be high titered).

Prewarm?  Hmm....

4 minutes ago, StevenB said:

Prewarm?  Hmm....

In the hands of an experienced serologist, a totally safe technique, despite, I'm afraid, what John Judd et al may say!

StephenB, since the inherent danger of a prewarmed technique is that you could miss a weak significant antibody, if you still get a positive reaction, then you haven't missed anything. I was just offering a laundry list of tools that might help you figure out why you have a cell or two reacting weakly with no discernible pattern.  

I agree in part: In the hands of experienced techs it has its use, but....

Using the prewarm technique to eliminate stray reactivity is simply not an appropriate use of the technique. Under no circumstance would I ever recommend to my customers that they use the prewarm technique to get around 2-3 or 3-4 stray reactions on a panel.   More significantly, the technique should not be used in the what would be the hospital's next step in this scenario which would be to find crossmatch compatible units using a prewarm technique.  And most likely that would be the tech's next step.

You ID a cold auto and want to eliminate it's interference, great.  You ID an antibody whose classification as "clinically significant" is based on its ability to react at 37C, such as anti-M, anti-P1, anti-A1 and you know for a fact there are no additional common antibodies present, also great.  But hospital blood banks should never use it to eliminate "stray reactions".  Heck, we don't use the prewarm technique in our reference laboratory to eliminate stray reactions and combined we have over 100 yrs of experience.

Using the prewarm for the right reasons...I'm "all in".  Using prewarm to eliminate "stray reactions", not so much.

Edited February 22, 20169 yr by StevenB

I apologize...didn't mean to hijack this thread.  

StephenB, please forgive me if I was unclear in my post , (although I can't seem to find anywhere in it where I advocated using the prewarm technique wantonly to eliminate "stray" reactions), as well as for taking the careless but convenient path of using "stray" instead of "occasional weak reactions whose pattern of reactivity does not suggest an apparent specificity". I agree wholeheartedly with everything you say regarding the potential pitfalls of prewarmed testing. (I am the slightly off-key bass in the back of the choir singing "Please don't prewarm that anti-E awayyyyyyyyy...........")

Definitely no reason to apologize, Dr. Pepper.  Anytime I hear or read about using the prewarm technique I tend to go on full alert....can't help it.  It's the reference tech in me, lol.  We see all too often the technique being used for the wrong reasons, so I have this almost "knee jerk" reaction to the topic.  Baritone/Bass here...as I've gotten older my "ear" is not what it used to be....maybe the back of the choir is a good spot for me too!

In my decades of hospital transfusion services, I like to say that I grew up surrounded by some of the most competent, highly-skilled blood bankers who performed every test in the books.  In the hands of the right folk, and that applies to any test/method, pre-warm, like any other technique can be performed with confidence.  Just my thoughts. 

I know the detection and id of antibodies have been missed in our BB/TS world, but I have always been comfortable with the prewarm technique.  When you suspect, pre-warm, and can then see clearly the anti-E pattern, this use to be gratifying.  In 2016 should I be afraid that I may have missed something else/prewarmed it away?  I am asking because I have 20 generalists rotating through Blood Bank  and I value your input.  I have only been here 8 months, with about 10 strands of hair left (9 as we speak), but that's ok, cuz we love what we do, RIGHT?  I digress.  The last SBB has a written procedure for Prewarming, however, preceding this is a page stating basically that prewarming can kill.  Back to sleep one more hour, I hope this makes sense.  Sincerely.

Oh!  In reference to calling HLA antibodies, after ruling out the common clinically significant antibodies to antigens on panel cells with confidence, we would still call for example, possible Bg, possible low prevalence, non-specific, etc.  Our IRL does not want these, and will guide techs when needed. 

Hey Connie,

Hopefully Malcolm chimes in because I believe we have slightly different opinions....

Our IRL rarely performs the prewarm technique and we see all kinds of blood bank problems.  Our reasons to prewarm are limited to:

1. Determine the clinical significance of certain antibodies; M, N, P1, A1.

2. Eliminate reactivity due to the presence of a cold autoantibody.  The patient's autocontrol must react at initial spin and the panel must demonstrate similar reactivity.  If the patient has a positive DAT with complement, even better.

Prewarming a recently transfused patient just is not done in our lab.  Prewarming reactivity that is seen at AHG and it is being difficult to ID is not done.  Neither are ever recommended to our customers.

My concern with blood bank techs who rotate in is that through no fault of their own, they lack experience.  I believe that in a pinch, this leads to decisions made off of vague recollections....stray, junkie reactions, no pattern that can be made out; must be a cold antibody so I'm going to prewarm to get rid of the problem.  And if its good for the panel, well it must be good for the crossmatch.  Reactivity at AHG, especially if you are using heavy-chain specific anti-IgG, should never be treated this way.

My recommendation; develop strict criteria for when it is acceptable to prewarm and hold your techs to it.  If they want to do something outside of that criteria, then it should probably be sent to a reference laboratory.

Shouldn't there already be strict criteria in the P&Ps for Everything done in the Lab?

 

Scott