crossmatch with EDTA sample

[CHILE]

Hello,

Sorry for my English, it is very basic but I will try to explain you my doubts. In my country (Chile) the crossmatch in the blood banks always has been tested in gel column. The glass beads column just its entering as technology, it is therefore natural we have some apprehensions, which I would like to be able to consult you.

We have always worked the crossmatch with tube Red taken to patient (sample) in order not to discard the hemolysis as sign of incompatibility. INNOVA suggests will work with EDTA tube, according to what I understand this anticoagulant chelates Ca ++ and Mg +, therefore eliminating the action of complement. Does that then happens with those hemolytic antibodies, example anti Le, are masking a kind of incompatibility? It has clinical significance?

Thank you and I hope you can answer me, greetings from Chile

[PAWHITTECAR]

Chile,

We work with EDTA tubes primarily and use gel technology. Everywhere I have worked in the last 20 years has used EDTA and have seen no problems.

Trish

[Dansket]

I stopped using polyspecific antiglobulin antiserum and switched to monospecific Anti-IgG reagent in 1980. We also have been using solely EDTA blood samples with Gel technology for past 16 years. Current thinking is that red cell antibody only detectable by anti-complement-complement reaction in the test tube is probably very, very rare. Use of Gel technology also eliminates subjectivity and variation associated with manual tube testing that probably contributed more to failure to detect incompatibility than the use of EDTA blood samples or monospecific anti-IgG antiglobulin antiserum. Additionally, we use computer crossmatch, eliminating 98% of anti-IgG crossmatches.

[Sadique.Kareem]

We go mid way to be safe. We do antibody screening of all patients samples (EDTA) using gel tech and monospecific anti IgG. To avoid the rare miss of complement binding anitbody we do cross matching by serum from red top tube and polyspecific IgG/C3d.

[Malcolm Needs ☆]

Hi Chile,

Sorry that I was unable to answer your private messages before, but I have been busy doing last minute Christmas shopping for my wife and son - and I can't afford a divorce!!!!!!!!!!!!!!!!!

We have been using EDTA samples in the UK for, probably, more than a decade now and, as far as I know, and don't forget, we transfuse an awful lot of people every year, there has only been one incident when a clinically significant antibody (an anti-Vel) was not detected in an EDTA sample that was later found to be detectable in a serum sample. Having said that, if I remember correctly, this did result in a fatality.

That having been said, you will NEVER detect all antibody specificities, or all antibodies within a particular specificity, with all techniques.

We are very comfortable using EDTA samples in the UK, and you will detect almost all clinically significant antibodies with EDTA plasma, even though you are correct in saying that EDTA chelates Ca++, Mg++ (and Mn++), all of which are required as cofactors in the classical complement system.

Admitedly, from a Reference Laboratory point-of-view, there are some drawbacks. Gross haemolysis in a test performed with an otherwise "clean" serum sample, gave us a hint that the antibody specificity was amongst H, Vel, PPkP1, I or, in VERY rare cases (even more rare than the proceeding specificities, Lea, but it does not prevent us "getting the specificity", it just takes us longer, as we no longer have the hint.

The other thing is that, rare as a truely haemolytic anti-Lea is, it is still of dubious clinical significance. It CAN and DOES occasionally case a "transfusion reaction", but the Lewis antigens are, of course, soluble, and not an integral part of the red cell membrane - in other words, they are adsorbed on to the red cell membrane from the plasma. As such, when Le(a+) blood is transfused to a patient with a "clinically significant" anti-Lea, the patient may have a transfusion reaction, but the Le(a) substance in the plasma of the donation will soon neutralise the anti-Lea in the patient's circulation, and the transfusion of Le(a+) blood can then continue, with no clinically sequalae. These days, with IVIg, and other such pharmaceutical (not sure I have spelled that correctly - useless at spelling me!) helpers, this is even more "true".

So, to cut a long story short, do not worry about going over to using EDTA plasma from serum.

[CHILE]

THANK YOU ALL, I am proud to have dialogue with people professional and loves her job. I'm more calm about it to be working with EDTA samples. FOR YOUR ANSWERS CAN SEE THAT MOST OF YOU WORK WITH GEL. DOES ANYONE with glass beads (INNOVA)?, If anyone can bring me in this technology I would appreciate OTHERWISE NO PROBLEM. MERRY CHRISTMAS to all.

ROLAN

[SMILLER]

One more side comment on the "EDTA sans compliment" issue. I would think that the compliment you are looking for is already attatched to the RBCs when the specimen is drawn. Therefor, the EDTA would have no effect on detecting what is already present. (We are not trying to detect compliment formation in vitro).

Scott

[Malcolm Needs ☆]

Um, actually, in the case of anti-H (from an Oh patient), anti-Vel, anti-I (from an ii adult) and anti-PPkP1, you may be Scott, but you would be REALLY unlucky to get one of those that you cannot detect without complement.

[SMILLER]

Another thing to be thankful for on Christmas!

Scott