Malcolm,

Thanks for this information. I am seriously considering switching to the Biorad reagents as my yearly contract order with Ortho is about finished. The information you have provided helps with that decision and will be useful once the Diamed system is available in the States.

I hadn't realized how much the Ortho gel system was different from Diamed's. My Ortho rep pointed out that other than the concept of gel column aggulitination (which is what the patent is about), the two systems are quite different. I would be nice to see a package insert/instructions for use for the Diamed gel cards to see what they say about the formulation. Does anyone in Europe have one to post?

I would be nice to see a package insert/instructions for use for the Diamed gel cards to see what they say about the formulation. Does anyone in Europe have one to post?

I'll see if I can scan one and post on here. Which do you want ABOD and Liss Coombs?

Yes, both please. What other sorts of IgG testing can you do on Diamed gel cards besides LISS? Enzyme, I assume? Anything else?

Yes, both please. What other sorts of IgG testing can you do on Diamed gel cards besides LISS? Enzyme, I assume? Anything else?

Were only a small lab so only do LISS - anything else gets sent away. From my past jobs in teaching hospitals it seems their use is pretty much unlimited. Sing it now! 'Anything tube can do gel can do better, gel can do anything better than tube'.

Some say gel is oversensitive any causes unnecessary further investigations but IME that is balanced by the fact that it can pick up clinically significant antibodies that have titres that are low enough to be undetectable by tube. Safety first and all that...

'anything tube can do gel can do better, gel can do anything better than tube'.

love it!!!!!!!!!!!!!!!!!!!!!!!!!!

love it!!!!!!!!!!!!!!!!!!!!!!!!!!

Love it toooo.

Hello Mabel, sorry I didn't reply earlier. I'm not often in front of my computer. The Ortho gel in the States is actually NOT that different from the DiaMed gel as, for lots of political reasons, the Ortho gel in the States is the Diamed formulation as used about 15 years ago. The cell buffer formulation is, I believe, similar but no longer identical. The Ortho 'gel' in Europe is hugely different as it is not gel at all but small glass beads.

Having said that, if you go to www.diamed.com you will get the BioRad immunohaematology home page. You can then select 'products'. There you have a product catalogue and, on the left hand side, you can select 'box inserts'. You do not have to have a special log-in to access them. I think this is easier than someone scanning them - especially the Coombs, which is really long. What you WILL see is the hugely increased number of products as compared to what is available in the States.

I hope this helps, and I hope I'm not breaking any rules by writing this - it's not a secret website

Best wishes

Anna

Just to add to my last post, I think one of the main differences is that in the States, you have to add antisera to a neutral card (for example, anti-C, c, E, e, K) whereas here in Europe it is already integrated into the card (both DiaMed AND Ortho). Anna

Can't scan them the writing is just too small Galvania's suggestion is a good one.

The Ortho 'gel' in Europe is hugely different as it is not gel at all but small glass beads.

Anna

Just to back up Anna's post Ortho's product is attached to glass beads and my understanding of ortho gel in the USA is that is essentially the same as the Diamed product in the UK/Europe. The Ortho BioVue as used in the UK is quite different to the Diamed gel

Steve:)

Hi All, Steve is correct, the Ortho product in the States (specifically North America) is a gel product very similar to the Diamed (now Biorad) product, but in the rest of the world their product is Biovue which is entirely different, it uses a glass bead filter instead of the gel filter as used in the other products. The methodology is different also with different volumes of plasma and different centrifugation times (Biovue has a shorter 5 minute spin). It is my understanding that the 0.8% cells supplied in NA by Ortho are also formulated differently from those that are used in the Biovue system. Hope this clears up some of the confusion between posts from different parts of the world.

When you get a patient who types weak D positive in tube, but strongly D positive in gel, do you only give them Rh negative cells?

I used the Ortho BioVue technology for the last 16 years and have never resorted to testing by tube. If the D reaction was positive by the Ortho BioVue then I treated them as D Positive. Having the two techniques only adds confusion. All the automated systems BioVue, Diamed (Biorad) and Immunocor are more sensitive than tubes and have been validated, I believe we must learn to have faith in the results produced from them.

Steve

:)

Edited November 15, 201113 yr by Steven Jeff

I believe the reason that some US gel users have gone to calling patients D neg only if they react less than 2+ is because of research out of Michigan (John Judd et al) a few years back that showed that a fair proportion of those reacting weakly in gel were partial Ds or others capable of making anti-D, not so much because they felt they were false positives.

I believe the reason that some US gel users have gone to calling patients D neg only if they react less than 2+ is because of research out of Michigan (John Judd et al) a few years back that showed that a fair proportion of those reacting weakly in gel were partial Ds or others capable of making anti-D, not so much because they felt they were false positives.

I agree.

We have loads of samples sent in for Weak D/Partial D differentiation per year, and when the reactions are really weak, you just cannot tell. Indeed, even when using molecular techniques, it is not always easy to predict whether or not an individual is, or is not capable of producing an alloanti-D.

I was involved in a case of S103P that produced an alloanti-D, and this had never happened before.

It is things like that which "keep you on your toes" (and keep me in a job, more importantly!!!).

Let me tell you a story - kind of a long one.

We recently saw a patient who tested 2+ with Immucor Series 4 and Series 5 anti-Ds on the Echo and 4+ by tube with Immucor monoclonal blend anti-D for confirmatory type. We transfused 2 units of Rh pos red cells the following day. Two days after that transfusion, we received an order to give 2 additional units of red cells. A new specimen was collected and run on the Echo. She typed as Rh negative with both Series 4 and Series 5 anti-D, though we can see some 'freckles' in both wells (weak mixed field). Tube testing with monclonal blend anti-D is now 2+. We repeat and recheck everything and discover that the blood she received was both parts of a pheresis collection from a donor that is weakly reactive with anti-D only in AHG. OK- fine, we would expect to see weakened reactivity, but her cells should still be the major population. Why so weak now? We open new vials of anti-D all around and retest. Same results. New lots of anti-D, same results. We test the Series 4 and Series 5 anti-D by tube and get 1-2+ results.

We follow the rule that says anti-D (all of them) must react 2+ or greater in order to call someone Rh Pos (Reference: Judd's Methods in Immunohematology - 3rd ed.), so we need to investigate further before we transfuse again. And now it gets more interesting. We have her redrawn (6 hours after the first blood bank sample) and pull some samples from hemo. The hemo sample and our blood bank samples (2 of them), all drawn 2 days post-transfusion, give us results all over the map, anything from 0 to 2+ by tube testing with all 3 reagents. We still need to transfuse our patient, so we play it very safe and give her Rh neg red cells.

I report the variations to Immucor. They decide to send out service to confirm that the instrument is functioning correctly. (It was - everything checked out perfectly.) Since every other patient we'd tested and our QC were just fine, Immucor did not consider it a reagent problem, but perhaps a patient related problem. The patient has an unusual diagnosis - LAM -(her meds are common ordinary) so I called our blood center reference lab to see if they've heard of the diagnosis causing problems with antigen typing. They are interested, so I send patient and donor samples. They try out 3 more anti-D reagents + gel and get results from 2+ to 4+. They refer the sample for molecular testing and put the story out on their network to their counterparts in other reference labs. Nobody has seen funky results like these with that diagnosis and a few ideas are tossed around.

Molecular testing comes back. They have determined that the patient is definitely a zebra of some sort, not a straight forward Rh Pos. They ruled out D variant and believe her to be some form of a weak D. They ruled out the common genetic mutations for the weak D, more testing needed to see if they could zero in on something specific. Without knowing which mutation the patient has, they can't determine whether or not she is at risk for making anti-D. The transfusion recommendation is to continue with Rh negative products.

If we hadn't transfused her with the weak weak D donor units, we wouldn't have given her a second thought. Maybe she wouldn't have ever made anti-D. Maybe she would have. If she goes to another hospital, they may very well call her Rh pos and transfuse accordingly. My lesson learned - just because the reactions with anti-D are >2+, doesn't mean we've dodged the variant/weak D bullet. There is still a LOT to be learned about the D antigen.

And I did give my friends at the reference lab something fun to think about - they should thank me! ;)

Edited November 16, 201113 yr by AMcCord
spelling

Thanks AMcCord.

Everyone should take that a salutary lesson, and also remember that Partial D III reacts strongly with ALL anti-D reagents, and yet can make a cracking alloanti-D!

I believe the reason that some US gel users have gone to calling patients D neg only if they react less than 2+ is because of research out of Michigan (John Judd et al) a few years back that showed that a fair proportion of those reacting weakly in gel were partial Ds or others capable of making anti-D, not so much because they felt they were false positives.

We also see the same results. Gel is strong and when you found a reaction that is 2+ or less, there is something wrong with the antigen, and the change that is a partial D antigen (change of antibody formation) is high. So threat them as RhD neg or find out why the reactions is only weak.

I do not completely agree with Steven Jeff that we have to trust the firm on what say completely. From experience I know the RhD/Crawford phenotype (only one epitope of RhD expressed on RHce) is very strong in Biovue gel, soon they are changing to a new monoclonal reagent (RUM-1) but did not take the effort of testing it with the RhD/Crawford phenotype (ignorance of laziness ??).

Peter

I do not completely agree with Steven Jeff that we have to trust the firm on what say completely. From experience I know the RhD/Crawford phenotype (only one epitope of RhD expressed on RHce) is very strong in Biovue gel, soon they are changing to a new monoclonal reagent (RUM-1) but did not take the effort of testing it with the RhD/Crawford phenotype (ignorance of laziness ??).

Peter

When you get a patient who types weak D positive in tube, but strongly D positive in gel, do you only give them Rh negative cells?

I might be a bit idealistic in suggesting that we have to trust the results from an analyser, but in the main that is what we do.

We have to draw a line somewhere, in the scenario quoted, how do you get to position of using a tube technique to check a strong gel result? Why was the tube technique performed in the first place?

Steve

:confused:

I guess it is neither ignorance OR laziness, but the impossibility of being able to test every reagent with every known D variant due to the fact that the cells are often like gold dust and are simply not available